Which type of spring is good?

hmm...well depends on your application.

if you're doing anything autox, go with the tein s-techs..

if you're more for show, go with eibachs or h&r

Tein, Eibach, and H&R are all worthy of street- and race-applications. The difference between companies (and their lines) are how much it lowers the car and the spring rates for the front and rear springs.