I finally took my car down to the mechanic to get my GC coilover kit installed. I already had Koni yellows on my car but I was starting to get rubbing on my wheel liner that was getting progressively worse. This was a combination of sagging upper mounts that effectively lowered the car and a wheel liner that was bulging into the wheel area. I'm not sure what caused the wheel liner to develop the bulge but the new liner definitely has no bulge and thus much better clearance. I also had David's billet aluminum Widefoot swar bar mounts installed at the same time. I ordered the GC kit with:

450lb 7" long springs front
350lb 8" long springs rear

It also comes with solid upper perches. Ride height is set to 25.5" front/rear.

The Koni's I am keeping at full soft for now.

I haven't really tested the handling at the limits but I can definitely detect the increaes in roll stiffness. The ride quality is a little harsher than stock but still streetable. I can't imagine how people ride around with 600/500 lb springs though. Even at full soft the Koni's provide adquate damping with these springs, whereas overall I felt they were overdamped for stock springs even at full soft.

Obviously the Widefoot mounts don't make a noticeable change in handling, but I should report that these are very high quality pieces, fitment was perfect, and they give you a little extra piece of mind with regards to ground clearance and protecting the frame rails (the mechanic said mine were fine).

Overall I recommend this setup as a nice compromise between street and track.

 

I guess it all depends on the package. I have 600lb front and 500lb rear springs and while it is a bit bouncy, it's surprisingly smooth and not jarring at all. I do think that if i had gotten independent springs and shocks that were not valved/designed for each other i would have a much harsher ride. I gotta give it to the D2 coilovers...they do a great job of taming that spring rate so you can have a track setup that's very streetable. Almost feels like a gokart. (Although, for the record, 600/500 is the stiffest i would go on the street. Any more and it would just be plain unpleasant.)

 

nice feedback. pomanferrari had some feedback on that setup as well. he tried a bunch of different spring rates and lengths till he found something similar to what you selected.