I would imagine that the DOHC engine is noticably heavier than the SOHC engine, enough to alter the weight distribution of the car to a point where handling will be affected. Yet, all of those manufacturers out there only make one spring or one coilover for all EKs. My guess is that most of the US companies like Eibach, Neuspeed, etc calibrate their products for the SOHC weight distribution and the JDM companies, like Tein, Mugen, Spoon, etc would calibrate their products for the weight distribution of Civics with DOHC engines. Am I right, or does the engine not really have a big effect on handling?

 

With aftermarket performance springs, the rates are so much higher than stock that the weight difference has a small effect.

Don't misinterpret that - it's still a SMALL effect - but not NO effect. Unless you're a regular track going monster, it's almost no real effect.

Shawn