After 75K miles on my original stock suspension, I just had a set of Bilstein B14 coilovers installed. The ride is sportier but still fairly compliant for street driving. The front of the car is now lowered (was not a priority) at least an inch and the rear doesn't appear to be that much. Note, the local shop said that they set the springs to the highest ride height. The issue is when I got the car back from this suspension job, whenever I accelerate hard from 1st gear into 2nd, I get shuddering in the 2nd gear. (I feel vibration through the floor of the car). I took it back to the local garage and they tried increasing the front spring height a little and it helped some, but I still get the shudder under hard acceleration.
Now that I have this issue I am seeing other posts that this seems to be happen when the car is lowered. I wish I knew this before buying the B14s.
Any suggestions are welcomed.

 

I have an R53, and just installed the PSS10's as well, and also get the same shudder. It's been about a month since I've put them in and it hasn't gotten worse, or better. I have not attempted to raise my car to lessen the issue, as others have mentioned.

All of my research has indicated that it's most likely CV related. Whatever it is, it's extremely annoying.

 

This is typical. Lowering changes the angles of the axles. It may be more pronounced on cars with more miles and worn CV joints. Mine is lowered by over 2 inches and I have some vibration in 1st and 2nd gear but it's not horrible.

 

CVs can cause vibration when the car is lowered, but I usually find it's on cars that are lowered significantly, like 2". If your car is at the highest setting on B14s in the front, OP, It's hard to imagine why you're getting that vibration. Are all 4 of your CV boots intact?

 

For vibration I'd check over all your suspension components and make sure nothing is bent and the bushings are in good condition. Definitely inspect your axles as well as those have been known to cause vibration issues.

 

Thanks all. I'll see about getting the suspension thoroughly checked, especially the components listed, and report any findings.

 

Update: The shop could not fix the issue, except for suggesting I change one of my front axles. So I took my car back to the local dealership and got the JCWs suspension instead. Now, there's no more shuddering. I'll be posting the Bilstein for sale soon. I put just a few hundred miles on the Bilstein so they are practically new.