Last updated: 9-Jul 2016

Disclaimer: Any modifications done to your car is at your own discretion and at your own risk. Do note that manufacturers will void your car’s warranty in the event of any modifications done to your car.

Don’t forget to check out Part 1 and Part 3 of my BMW 320d modifications.

Part 2

Here is part 2 of my BMW 320d modification guide. You can refer to part 1 here. As much as I can, I am trying to incorporate both the E90 and F30 models of the 320d into this modification guide. Well frankly, it isn’t really much of a guide but more of an awareness of the kind of modifications you can attempt on your car.

Exhaust Modifications

Changing your exhaust can also improve your car’s performance. Modify this at your own risk, unless you decide to use the original BMW M performance parts. What sort of risk? Well with shoddy workmanship, you can face a lot of problems.

• BMW Performance exhaust – I have seen a number of the E90 320d cars sporting this exhaust. Frankly you won’t get much of a difference in terms of exhaust note mainly because, its still a diesel. One of the more expensive option but it comes with warranty and a peace of mind. There was a case where someone compared dyno results between a 320d using this exhaust and one without. There were some differences in terms of power, close to about 10bhp. I haven’t seen one available yet for the F30 320d. 
• Aftermarket exhaust – So far the only one I have seen available here in Malaysia is made by Jetex. This is only the catback portion with a 3″ diameter. The exhaust note sounds a little lower, love the growl from this exhaust and it does sound nicer compared to the BMW performance exhaust.
• Custom exhaust – This is one of the options you can take, to fully customize your exhaust system from the downpipe all the way to the catback. For the E90 320d, most stage 2 modifications include a downpipe change to around 3″ in diameter. A fully customized exhaust system sporting a 3″ diameter all the way can be pretty costly and the price will depend on the material used. With a larger diameter, you should be able to achieve higher horsepower at the higher RPM range but will sacrifice a bit of torque. Beware of custom built exhaust as you may not know how loud it will be and what sort of droning effects it may cause.
• Removing the catalytic converter – This is also a method to allow better air flow through the exhaust. If you are an environmental person, then I would suggest against this. If you want a compromise then go for a race high flow catalytic converter. This does provide a little bit more power at the top end. Totally removing the catalytic converter would result in extra black smoke coming out from your exhaust.

Handling V2.0

Apart from the usual tower bars, ARB and suspension, to further improve on the car’s handling in a more hardcore manner, there are options for the real hardcore.

•  Urethane bushings – Powerflex makes a wide variety of bushings to fit many BMW’s and they do have models for the 3 series. Using this to replace your stock bushings, it definitely makes you feel that everything is tightened but the downside to this is that you feel everything. By that I literally mean everything. Because the bushings are harder, you feel more vibration coming from the road but you can consider that a good and bad thing. 
• Foaming – Can you put in a special type of foam inside your car’s chassis filling up the gaps. Once the foam dries up, you get a stiffer chassis with less flex. There are several vendors who offer this service, AutoFoam KL comes to mind. One of the key benefits of this treatment is that you also make your car feel solid and quieter as well.
• Roll cage – This is the ultimate way to stiffen up and protect your car especially during motorsports. So far the only BMW to come out straight with a roll cage from the factory would be the BMW E92 M3 GTS. I happen to know there is one available at Naza World going for around RM800,000.
• Lower Arm Replacement – You can opt to replace your lower arm suspension parts with those from the M3. Online stores like Turner Motorsports have a full kit available to be purchased online. This can be used in any E9x chassis. An alternative is to lookup the part numbers stated in the link and purchase the parts directly from our local stockists such as Bavarian Auto and Stuttgart.

Exterior Modifications

There are plenty of people who like only exterior modifications. Whether it may come in the form of body kits or rims.

•  Bodykits – For the F30, the M-Sport bodykit and trims are available and the full kit ranges from RM15,000 to RM20,000. But I heard that the M-Sport versions of the F30 320d will be coming soon to Malaysian shores. Brands such as M-Tech, Wald, ACS and Hamann have their own set of bodykits. In Malaysia, we also have the replica M3 bodykits which will fit the E90 320d because the original M3 bodykits such as the bumper will not fit the E90 cars. 
• BMW Performance Parts – BMW also makes and sell the carbon fibre bits which add on to your existing car’s bodykit. Because they are made of carbon fibre (CF), they cost an arm and a leg. For the BMW 3-series E90, you have the front CF splitters which sticks to the bottom part of your front bumper, the rear CF boot lip, the rear CF diffuser and the CF wing mirror covers. They also have the matte black kidney grill available as well. Aside from getting the original BMW parts, known eBay OEM knock offs have surfaced for a tenth of the price.

I will stop here as part 2 of the modification guide. Will proceed with the next posts focusing on the interior bits. Will try to get more photos in here to allow readers to visualize the parts and modifications.