Has any one just lowered the rear of the car only with the roush springs if so can you post a pic of your car.

 

Yes, many people have done it including myself, it lowers the rear about 1 inch and the car sits completely level, this is a mod you will never regret and besides lowering all 4 corners makes for a crappy harsh ride. Lowering only the rear you can't tell the difference.

You may need an adjustable panhard bar, because if you lower the rear all the rear axle assembly is going to move a bit to the drivers side.