Viper Spring Technologies Coil Over Springs. We use Viper Springs on most of our coilover builds. We are an authorized dealer of Viper Springs. We can provide other springs just contact us for a price and availability.
We typically recommend using a lower (Main) spring that is 2″ longer than the shocks travel length.
Jeep Liberty we recommend a 12" Spring
Jeep Grand Cherokee / Commander we recommend a 14" or 16" Spring