It depends on what you're going to use the car for. If you are only concerned with lowering it then go for whatever will give you the ride height you want. If you want to be able to corner then you need to pick whether you want to corner on nice smooth roads like you find at a track or if you want to corner on uneven roads which you'll most likely find on the street or public roads. Once you decide that then you'll pick between coils (track) or shocks and springs (street). Further than that I wouldn't know what to tell you. Good luck.