I just recently installed a Rough Country 4" lift on my truck. I went with the kit with new springs (no blocks) (a) because my trucks original springs were sagging and (b) because I don't like blocks. The kit came with everything including springs (f/r), shocks, and steering arm. It also had new extension brackets for the brake lines, but I went with stainless steel. They look better and have much more room than the brackets would have provided. I also had to get new tubing for my diff breathers as they would not reach comfortably after the lift.
The installation was pretty simple. It took me a couple of evenings. The hardest parts were getting the truck up high enough so that the axle would clear the new springs once dropped and getting the steering arm off. I used a tie rod separator to get the drag link off and a 3lb sledge with a bit of banging to get the arm off. But it wasn't bad at all.
I originally had 32s under my truck they filled the wells nicely but rubbed slightly when turning with a bump or incline. The 4" lift and the non-sagging springs raised the truck about 6" total. My 32s looked pretty small after that. I just had 35s put on yesterday and they look great.
Thats the combo I would definitely recommend. I know you said you were looking at a Tough Country lift, but I would recommend the Rough Country lift. You can order it direct from them for the best price. They are very friendly and helpful. You can find there number at <A target="_blank" HREF=http://www.roughcountry.com>http://www.roughcountry.com</A>. If you search this site, you will find nothing but rave reviews of their lifts and their prices. I am very happy with how complete mine was, how easily it all installed, and the look and ride of it after the fact.
85 GMC Jimmy, 305 w/TH700-NP208, 4" lift, 35X12.5 BFG MTs, 15x10 Hellcats, Smittybuilt tube nerf bars and bumbers