QUOTE(Eric_Shea @ Feb 2 2008, 09:02 PM)
Koni's would ride much better (in my personal experiance). Koni's are also adjustable.. like it stiff? Turn the dial.
Depending on what you want to do to your car... your spring rate can vary wildly. I like stockish 100lb type springs for most activities. If you get serious about racing or autocrossing the you would want to tune the suspension front and rear depending.
If, like you say, you've simply dialed down your stock front end then a 100-140lb spring out back would both, lower it a bit and an adjustable perch would allow you to dial in the specifics.
There are a couple types of perches and springs. Andy is talking about a threaded perch and smaller Eibach springs. You can also get by with a 3 position stock style perch.
thanks eric.