I just recently installed some Cobb Tuning Springs on my 07 WRX and I hear a clunking type noise from the rear struts. At first I thought it was the top shock bolt (17mm) and top hat nuts (12mm) being loose but they were both down tight and torqued right. So now I don't know what it could be, the car is brand new and I checked everything on the strut assembly. I don't hear it all the time only on some bumps. Anyone else with these springs or similar have the same problem???

 

Do you need a bump stop for the cobb spring? That could be the problem but I'm not sure if their installation requires one.

 

I have cobbs on my 05 sti and no problems. The front isn't dropped enough and the back is perfect. I have no issues like you but my camer is so bad that a 1 inch interior edge of all 4 tires is worn. Highly recomend adjusting camber. Look into the notorious problem with stock struts going out on the 04-05. They had a problem with the struts going out at low miles. Could be that. Hopefully dealer will take care of that but you have modified so you may want to switch them back to get those replaced if that's the case.