If you do calipers, do the matching rotors. I used the 3.0 GEN II stuff for convience since they were the easiest to get. When I did the upgrade, I used the old rotors. The first hard stop warped them good. Now I do matching rotors and calipers. Don't forget that you have to trim the backing plates to make them work and the little bracket on the caliper that holds the short metal line.
I had an issue with using new bolts on the hub was that I really couldn't get my socket in to hold the bolt. I used socket cap bolts instead.
Gen II rear springs do give a slight lift. I feel that they handle better with the newer Coils and it tows better too. I feel the Gen II UCA's make it ride better, but if you don't lift it or do bigger tires, I would leave it. My current Gen I has 265/75R16 and still has plenty of room.