The BMW E46 330i or 330Ci is perhaps one of the most ubiquitous BMWs. It straddles the line between being an enthusiast’s performance car and a normal commuter. These are the BMWs those of us in our late twenties and early thirties remember as the ‘new’ BMW, and what nearly every ‘hip’ mom drove back at the beginning of the new Millennium. While the automatic sedans and convertibles that were more prevalent tended to have non-enthusiasts behind the wheel, the manual-transmission option, as well as the coveted ZHP model, flew under the radar as a pseudo-continuation of the US-Spec E36 M3. While it’s big brother, the E46 M3, sported the S54, individual throttle bodies, and 333hp, the 3.0-liter M54 found in the 330i more closely resembled the US-Spec S52 from the E36 M3. It splits the world between the outgoing, boxy, extremely balanced performance of the old M3 and mirrors the futuristic round styling of the modern E46 M3. The 330i offers, as many have discovered, a good looking, well-performing, engaging, and affordable platform to build. Today, we’re looking at improving the looks of your E46 330i or 330Ci to bring it into the modern trends for an aggressive, yet practical, style upgrade.
If you’ve just picked up a 330i, one of the best upgrades you can make is a set of coilovers. The E46 is a fantastic chassis. It maintains a near-perfect 50-50 weight distribution, drives incredibly well, has a fairly quick steering rack from the factory, and is favored as the perfect platform for club racers, Spec drivers, and drifters alike for its capabilities. It’s also quite like many older BMWs in that it responds well to tuners who want to make the chassis their own. With a set of coilovers, you can improve the look by going low while also making a significant upgrade in terms of handling. If you’re primarily focused on dropping the car down to the ground static and maybe hitting the track a few times a year for drift events or some HPDE events, BC Racing is a great place to start for some highly adjustable, yet still affordable, coilovers. For someone looking to have a dedicated track car, we suggest either TC Kline if you have a higher budget or Bilstein coilovers for the more budget-conscious track rat.
Sway Bars/End Links
Pairing with the lower center of gravity and improved handling from the coilovers, a set of beefier sway bars with adjustment settings, fresh polyurethane bushings, and some adjustable end links are critical. The adjustability of the sway bars will allow you to play with how your E46 rotates through the corners and can help you induce more oversteer, reduce understeer, or balance the car out to your liking. Naturally, the polyurethane bushings that are included with most upgraded sway bar kits will help reduce deflection and increase responsiveness. Lastly, the adjustable end links will help you eliminate preload and prevent binding that may occur with your E46 lowered aggressively. This combo will effectively eliminate body roll and help keep all four tires firmly planted in corners, or allow you to fine-tune your handling characteristics for your desired behavior. We quite like H&R front and rear sway bars for our BMW, which is what we suggest for yours.
Bump Steer/Roll Center Correction
Another important improvement is bump steer and roll center correction. As you lower your E46 330i, the suspension geometry changes. Your roll center is lowered to a point ‘below’ the ground and you lose some of the benefits your stock suspension geometry offers while gaining the benefits of having a lower center of gravity. This is where bump steer can become an annoying side-effect. Bump steer is just as it sounds; steering changes induced by uneven road surfaces that are not made by the driver, but rather, are the result of improper suspension geometry from lowering your car. The Turner Motorsport Bump Steer and Roll-Center correction kit is effectively a must-have for any lowered E46 that still need to steer and drive like it did when it was stock. This way, you have all the benefits of proper suspension geometry with the added benefits of improved handling from a lower center of gravity and reduced body roll. This handy video featuring Mike Day at Turner Motorsport explains it all quite well.
It’s likely that your second-hand E46 330i suspension will start to show its age with the previous upgrades, so your next replacements should be in the front control arms. New front control arms with fresh ball joints will help restore the responsiveness and firmness of your steering feel, but it’s also a good time to include a set of Turner Motorsport Monoball FCABs. These spherical bearings allow for all the movement your FCABs need to allow for proper articulation, but completely eliminate deflection for the sharpest turn-in response and steering response you can achieve with your E46. The benefit of Monoball FCABs over Delrin or Polyurethane is that they have absolutely no deflection while they also don’t suffer from NVH to the same degree. You’ll be able to guide your E46 330i like a laser through corners and won’t have to feel all the vibrations or feedback that comes with other upgraded FCABs. In this video, Craig explains all the different types of bushings and bearings offered by BMW and Turner Motorsport, ending with an in-depth look at their exclusive Monoball upgrades.
While the coilovers will likely include a set of upper strut and shock mounts in their assembly, there are a few other mounts and bushings that need to be replaced as well. With all the upgraded suspension components mentioned on this list so far, and the ones that will follow, you’ll notice the next weak points are all those mounts and bushings throughout the car that feel sloppy. Engine, transmission, and differential mounts are a great place to start. Even replacing tired old mounts with factory ones is a step up, but if you want to eliminate deflection and help send as much power as you can to the ground, it’s a good idea to just go ahead and upgrade. If you drive your E46 regularly on the street, we don’t suggest solid aluminum mounts, but polyurethane engine, transmission, and diff mounts are a great compromise. They’ll reduce a considerable amount of driveline deflection without increasing the NVH to unbearable levels for long drives. You’ll notice them, as there will be more vibration in the cabin and through the steering wheel, but it won’t kill you. The most important thing to remember is to keep your mount material consistent in all three locations. If you have soft engine mounts with stiff transmission mounts, it’s going to feel like the car is tearing itself apart. Just make sure that whether you decide to go with OEM rubber mounts, solid rubber upgrades, polyurethane, or solid mounts, you select the same material for all the mount locations. The Turner Motorsport Polyurethane Engine Mounts are a great place to start. If you want the full race experience and prefer solid mounts, we also offer the Turner Motorsport Solid Aluminum engine, transmission, and differential mount kits.
Rear Subframe Reinforcement
Common failure points on any E46 are the rear subframe mounting locations. These tend to crack, tear, and even fail completely on cars that aren’t driven as hard as you’d think for it to happen. The only solution is a set of weld-in rear subframe reinforcement plates to both fix the problem and prevent it from happening in the future. We suggest this happen when you replace the rear subframe and diff mounts as mentioned in the previous section.
Rear Trailing Arms
Last in the suspension and drivetrain component of initial upgrades is a set of adjustable rear trailing arms. Much like the bump steer issue in the front, the rear of your E46 suspension geometry also suffers from lowering on coilovers. At a certain point, the factory rear trailing arms no longer allow for the suspension settings to align correctly for the BMW-approved standards and will need adjustable components with a wider range. When you lower your E46, it tends to camber out negatively, which needs to be corrected. Adjustable trailing arms, or camber arms as they are often called, will allow you to bring the camber back into spec for proper alignment. Inversely, if you are just shooting for the cambered-out ‘stance’ look, rear trailing arms will allow you to induce more negative camber to stuff wider wheels under your rear arches for big tilts. Turner Motorsport offers both ‘street’ and ‘track’ versions that feature either rubber bushings or Heim joints for their appropriate use in either location.
Perhaps the most important cornering upgrade you can make, competent brakes allow you to stay on the throttle longer and spend less time on the brake pedal. The fastest drivers aren’t concerned with how long they can spend on the gas, but how little time they have to spend on the brakes. With a good set of pads and rotors on all four corners of your E46 330i, you’ll have most of the puzzle. However, for the best feeling, it’s important to choose a brake fluid that meets the temperature requirements of your chosen motorsport and braided steel brake lines that help improve pedal feel. While it can be tempting to ball-out and spend money on a big-brake upgrade, even at higher levels of motorsport competition, you don’t really need it. Performance pads, rotors, brake fluid, and stainless lines are all you need to significantly improve the stopping power of your E46 and feel confident as you head into braking zones for corners. We have a brake service kit and brake upgrade kits that can either bring you back to how it performed when it was new or improve your E46 330i brakes with our performance kits.
Once again sitting squarely in both the performance and visual upgrade categories simultaneously, a set of wider, lighter, and better-looking wheels belong on your E46 330i to help set it apart. In terms of performance, lighter wheels offer lower rotating mass so your engine doesn’t have to spend as much energy turning them when that power could be better used propelling your BMW forward. As well, wider wheels allow you to run bigger tires for more surface area on the road and better handling. Whether you just want to look good, handle better, or both at once, APEX Wheels offer the widest selection of BMW-specific fitments and styles that take inspiration from OEM options with significant improvements. They also offer fully-forged options now for even lighter, more durable, wheel choices. Whether on the street or the track, APEX Wheels are our top pick for your BMW.
Finally, into the last segment that is simply just for looks. The E46 330i has an attractive face, but the more aggressive MTech front bumper option is our favorite. We offer a conversion kit that includes an MTech bumper cover so you can have the coveted looks that show off your discerning BMW taste from a bolt-on kit. If I had an E46 330i, this would certainly be on my list. Note – this only fits sedan E46 330i models.
For a bit of style in the rear of the car, the Turner Motorsport High-Kick Rear Spoiler is just a hint of motorsport inspiration to make your E46 330i look more aggressive and enthusiast-driven than a plain, shaved trunk displays. It isn’t egregious, but it does give that little something to your E46 rear that we think it was missing.
Finally, you can’t have the looks and performance without the sound. While nothing on this list has added horsepower, what it has done is allow you to use all the horsepower available from the stout M54B30 more effectively and handle it well around the track. The last thing you need to complete the package before you start making horsepower improvements is to give it a hearty exhaust note that lets the straight-six sing those glorious straight-six noises and looks more appropriate exiting the back of a now-modified E46 330i. There are quite a few options to choose from, and it really comes down to your preferred look and sound, but we would like to offer our suggestions for your perfect E46 330i exhaust. If you are budget-conscious, Scorpion’s Cat-Back is priced reasonably well, or you can opt for the muffler by itself without having to fork over nearly $1,000. If you simply want the best you can buy, Supersprint is our go-to for that choice. Finally, Borla offers a good middle-ground between these two options with their E46 330i Cat-Back. But again, forget the price, focus on what you want based on how it looks and how it sounds, because those are the only real benefits you’ll find with an aftermarket exhaust system on this car.