Former autocrosser, I'm running GC coils/springs on Tokico struts. Sorry, don't know the spring rates (nor have I run this car yet) but I seem to recall a counterintuitive tip: run softer springs in the front than the rear.
I remembered this because I would think that the engine/heavier front would call for a stiffer spring, but I read some article that said the opposite actually improves handling. You may want to look into beefing up the sway bars while you're at it.
If you don't already know, coil-overs alone will put you into the STS class. So if you don't have other mods, you may not be too competitive... (which is why I've never run my civi
)
Good luck!
