Hayaku, I am not that technical. No, I don't know the spring rate.
Diaz, at high speed turning or lane change body lean is reduced a lot, and that is major improvment.

thanks!

if body lean is reduced, then the spring rates are higher then stock. since these springs lower the car more, the car will roll more (yes, counter intuitive, but thats physics - instantaneous centers are moved further away from the car, giving it more body roll for a lower car).

That certainly does sound counterintuitive, but I can see your point wrt "roll". However, I believe lowering the vehicle will make it "lean" less and in turn, provide "flatter" cornering, which feels good from a handling perspective. If you did just the opposite – increased the height of the vehicle, I’m sure it would tend to lean more. It would make it very obvious, for example, if you took it to the extreme to prove the theory – raise the car 10 feet off the ground. Can you picture that going fast around a sharp corner? Just my $.02 guess...

Hayaku, I forgot to mention that Eibach claims the spring rate is progressive. I feel that being true, for it does not feel harsher than stock SP with minor bumps.

how much do you think istallation will be for these springs, how much should I expec to spend on the install?

How about H & R springs? i see alot more people using H & R :dunno:

there's alot of physics at work here that most people will not understand and i won't go very deep into it because i generally end up talking only to myself on this subject. only suspension engineers would be able to keep up, and i still consider myself a newbie on this compared to my race car builder.

here's a brief and simple article by our good Dr G. describing what happens when you lower a vehicle: http://www.e30m3performance.com/myth...t_transfer.htm

those were available first. not many choices in this area...

my guess is about $200-300 since its only the front that requires the work. but you will need an alignment after the springs are installed so add another $100?

Interesting stuff! Thanks for the pointer!!