I have a base model 2011 E90 335d (no sports package and no mods). Since everyday street handling is my main interest, I evaluated ways in which I could improve the handling of the car without doing anything too radical. I have had the car for a little over three months, and I felt that its handling was unbecoming a BMW, in that it wallowed a bit over slight elevations or depressions in the road at highway speeds, and it didn’t settle down promptly when encountering road imperfections. I didn’t particularly want to lower the car even though I think it looks a bit better when that is done, as I don’t plan to take it to the track all that much. Having said that, I didn’t rule out the idea of lowering it an inch or so. So, I evaluated changing the springs, the struts/shocks, the sway bars, the wheel size, and the tires. I went against my basic instinct of not lowering it, and evaluated the H&R spring upgrade (1.3 in in front and 1.2 in in the rear lowering) and some Bilstein or Koni strut/shocks (which I have done in the past with my old 2002 and a Jetta I had. But couldn’t find for the 335d anything that looked like a matching set, and I didn’t have the money or interest in experimenting. Then I looked at the Bilstein B16 coilover kit, which seemed to have promise, but got a bit nervous from reading the blogs. Again, I didn’t want to spend money and be disappointed. So, I backed off and yesterday I had installed just some Bilstein B6 Sports struts/shocks, nothing else. There is a noticeable difference. When the springs are energized, these dampers quickly “dampen” the oscillations the way I think they should, without making it really any harsher than the run-flats already make it. It is slightly more twitchy on less than perfect pavement, but nothing that I dislike and it seems to give me better road feel. At Speed in Hanover also gave me a nice alignment. So I am quite pleased with the results of what I have done so far. Next steps? Well, I thought I might upgrade the rear sway bar a tad by installing the sway bar from the Sports Package. I bought it and haven’t received it yet. But to my chagrin and embarrassment I discovered after that fact that the dealer sold me a sway bar that is no different than what I have installed. Seems that the rear sway bar for the base model and the M Sports Suspension option is the same, although the front sway bar is the same. So now I am starting to research the H&R rear sway bar, which is 20mm vice the OEM 13mm. I am a bit concerned that I will change the car from being an understeerer (which is OK for an amateur like me) to an oversteerer (which would require me to enhance my skills more than is probably possible). Still pondering this. Don’t know whether I will mess with the springs or not. After they wear down I will eventually replace the run-flats with something else. Constructive comments are welcome.
