From what I know, there are three spring kits, the H&R is the most aggresive at 1.4", the ...
From what I know, there are three spring kits, the H&R is the most aggresive at 1.4", the Eibach is in the middle at 1.1" and the Kleemann which is under an 1". It depends on the car. The coupe is already 1/2" lower than the sedan to begin with so I would not hesitate in lowering the sedan more than the coupe. You can always cut the factory springs to any height you chose, the problem being how much do you cut, it's all trial and error. Lowering springs will affect your ride and so will the larger wheels you would end up sticking under there to complete the look. The Kleemann is the least aggresive and likely gives you the best ride and least camber adjustment problems. If you don't compensate for the camber angle your tires will not last long.
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