springs < coilover kit (sleeves) < coilover system (full)

I run Skunk2 coilovers and they work great. The adjustability will be very missed if you just get springs and you never know if they will all settle at the same height. Get c/o's.

BTW, they are trial and error. You put them on guessing where they will make the car sit. If you don't like it you just jack the car up again and change the height. It's easy.