[sensazn54]

Hey all. So I have a 2009 335i Convertible with sports package with 79K miles. I was told by the dealer yesterday that I needed rear shocks. I wanted to get an idea of what everyone is doing when the time comes to replace shocks or springs. Should I stick with the OEM's or should I go aftermarket or coil overs? If not the OEM what is a good option for about the same price of the OEM? Thanks in advance for your inputs.

[chris @ eas]

Well now that all depends if you are trying to lower your car or not. If you do not want to lower your car stick with OEM. If you want to mix it up a little and lower it a bit get some coil overs. Let me know if you have any questions about coil overs!

[sensazn54]

With the sports package my car is sitting pretty low already so I probably wouldn't want to go any lower. Which coil overs are you referring to? How much do they run? Thanks.

[jfranci3]

If you're not going to change the ride height, coil overs are pointless. When people say coilovers, they mean they want shocks with ride height adjusters that the springs sit on. Usually these people want to really lower their car, want to change spring rates and corner balance their cars often (racing), or just want a part that sounds cool. In some cars, there's a benefit to a 1:1 shock spring motion ratio, but your front struts are already a coil-over-shock setup and the rears usually get a separate spring/shock as there's a packaging issue back there.

If you're not going to lower the car, any spring kit is pointless. The only reason to change the springs is to lower the car. Lowered cars need higher rate (stronger) springs.


You sound like you're happy with the ride height, just replace the shocks and you'll be happy. The sport pkg cars ride low as you'd want for a daily driver. OEM Sachs are decent, Koni or Bilstein if you want get crazy.

[sensazn54]

Makes sense. Thanks for the info.

I am happy with the ride height but wouldn't mind a slightly stiffer set up. Will the Koni's or Bilstein give me better handling?

[jfranci3]

When you say "Stiffer" what you really mean is "more responsive", right? Obviously, you're not looking to make hitting bump less enjoyable. You want better handling, more body control, and better feedback from the car.

A few things you can do here:
1) Monotube shocks (eg Bilstein B6 / B8, not B4) - These have a larger piston in the shock and do a better job than the OEM/twin tube shocks of controlling initial movement of the suspension and low speed dampening (handling/body control). Bilsteins will make the car sit a bit higher though (about 1/2" on my car) - this is because there is about 100psi of nitrogen pushing on a larger strut piston compared to about 30psi on a normal shock.

2) Suspension bushings - put stiffer bushings everywhere. It's like going from a butter knife to a steak knife. The M3 front control arms are a good place to start. People say these add noise/vibrations to the car, they really don't. You might put your struts/wheels in a bit more danger if you hit a deep pot hole or curb if you go full solid, but it's not a huge concern. It really allows the rest of the suspension to do it's job.

[Wolf 335]

One thing to note is that some guys have complained that the ride height is slightly higher when doing a direct replacement from OE Sachs Sport to Bilstein.

From my research, as I am looking for replacement as well, idea is to stick with the original Sachs struts if you want to maintain the original ride height.

[jfranci3]

The difference in ride height with bilsteins on a sport package car takes the car up to std suspension height. Not a big deal, but it's there.