I always hear people say rough suspention and hard suspention. One is better than the other.......right? which one is best for performance? how about the small adjustable springs? which are better the lowering eibach typer or the ground control adjustale type?

make this clear THANKS

 

If youre talking about ride quality rough means its a harsh, bumpy ride. This is caused by high spring rates and/or being at a very low ride height. Springs are rated by how much force it takes to compress them one inch. So the higher the spring rate, the stiffer the ride will, but less body roll (good for handling) You have to find a compromise that is comfortable to you. As an example I have H & R sport springs which are rated 276lb/in. Thats a fairly soft spring for the street. The lower your car is the higher spring rate you need to keep from bottoming out. For the street I think 1-1.5" lowering is fine. As far as I know Eibach doesnt offer an adjustable spring, but they supply the springs to Ground Control for the coil sleeves. I cant remember the rates for OTS Ground Controls but I think its 350F 280R or something. Thats a decent rate to have good handling and still decent ride comfort.