Not familure with a 3" lift kit unless it's a body lift, So I'll assume you're talking about a 4" lift. If you buy a complete lift kit it should have everything needed. (Springs, shocks, raised steering arm, extened break lines, ...ect.) You may also need to get longer driveshafts. For the rear you have a few choices. Blocks are the cheapest way to go, and alot of people use them. I personally don't like blocks. You could go with full springs, some people don't like the ride of those though. There is also the shackle flip, little bit more work, but is nice in my opinion. There are a few things to consitter befor doing a lift. What is your goal ??? What do you plan on useing your truck to do ??? How big of tires do you want to run ??? Everything you do effects one thing or another.