Brandon, you really need to think about the whole system as a whole rather than throwing spring rates around. Sway bars, tire size damper valving also play an important part in the overall driveabity of the car. Also, camber plates, solid bushes and spherical bearings in the top mount of your rear coilover might not help you one bit on the roads you describe and will transfer a lot of noise into the cabin.
My daily driver on smooth FL roads handles very well with 250f 350r and 968 M030 sways, coilovers all round with Konis and stock Euro right height. However, I do get a lot of noise/vibration transfer into the cabin from the upper shock spherical rear mount. I use stock top mounts at the front so no increase in noise there.
If I was on any other roads I would look at 200f 300r and would probably stay away from coilovers at the rear and get the rates I want there from a torsion bar change and adjust the handling aspect I want with sways and tire sizes. I also think that the original Boge/Sachs shocks give a better and smoother street driving experience, I find Koni valving a little harsh on the lower >300 spring rates and have mine set full-soft.
My set-up on the dd is from Ground Control, my track car uses KW Variant and is a different story altogether. FYI here are some (bad iPhone) pics of mine:
Front:
Rear:
