There are 3 kinds of H&Rs. Race, Sport NA, and Sport SS. The two sports lower about the same in the front, but the SS lower more in the rear. As far as getting just the rears, I tried finding a vendor who would sell just the rears and came up empty. I ended up just buying an entire set of Sport SS springs, and the drop is awesome

 

dude, I have the sport ss H&R springs on my ss/tc and its just like this. I have 3 finger gap rear and 0 fingers in the front. Get B&G springs and use the rear only and it will be perfect. that's what im doing...TC cobalts never lower as much as base and SC models...