Eibach springs are excellent - I just had some Pro Kit springs fitted to my C320 and have had them on my Impreza WRX and Mondeo ST24 in years gone by. They are progressive rate so offer a fairly smooth ride over the bumps but stiffen up when cornering. They lower the car by about 30mm. A worthwile upgrade if you want to improve handling without losing too much ride comfort. That's all I got