JBA and RRO have 1/4" spacers. They result in ~1/2" of lift. You can't do 1/2" without changing the strut mount studs since there's not enough threads there.

You can probably squeak out another 1/4" or so depending on where you clamped the strut forks. See here:
http://www.theultimatejeep.com/showt...ll=1#post18958