I actually have the camber kit on there. I would suggest it, just for the sake of your tires. Also some places would not do an alignment on the rear without them being on there.
I have no problems with clearance, so far, and the ride is not bad at all either. Only thing I suggest to watch is when you get done with the springs and take it to a place to get an alignment done, make sure they don't have a steep incline on the rack. When I called Dobbs to see if they could do mine, they said they cannot do lowered cars, because of their racks, and to watch where I take it to make sure I didn't get any damage to the body.
I would deffinately recommend getting the pro-kit.
Bean,
I love those wheels on your color car, looks really good.