In Reply to: lowering springs posted by b on March 30, 2000 at 20:49:19:
Lowered springs require sport shocks designed for shorter springs so they won't bottom out. Unless you really go to near-race springs, the aftermarket stuff is only 15 to maybe 25% stiffer, and won't affect ride quality much. The shocks, however, can affect ride quality greatly. I have RD springs and Bilstein Sport shocks. If I had the time and money, I'd rip those %$*& Bilsteins out so fast the fluid would boil. They are fine on fairly smooth roads and small road irregulatities, but anything significant and they act like they're locked up. I'm amazed I haven't damaged a wheel yet.
My understanding is that, from stiffest and most lowering to least, the order is Eibach, H&R, then RD or Dinan. RD (that's RD USA, not RD Sport) may have gotten stiffer. They used to be like Dinan, but their sway bars have gotten thicker in the past couple of years, so they may have toughened the springs, too. I don't know where the others fall.
I will disagree with others here. Yes, you can cut the springs, but, yes, you will have to take them off the car. It is rare for these BMW springs to sag, but it's easy enough to do a ride height check beforehand to confirm that you have good springs (see the Bentley manual. Cutting the free length just over an inch in front and just under an inch in back will about match the RD springs, maybe a 15% increase in spring rate, which isn't much. I found that the wiresize of the RD springs was actually SMALLER than the stock springs. Metric Mechanic used to give info on spring cutting for the E32 and other earlier cars, but doesn't seem to be updating anything any more.