I have a Rough country 6 inch lift kit and love it. They offer an excellent warranty and went over and beyond for me when i ruined a part with my own stupidity during install.
35 inch tires are what is recommended with the 6 inch lift. Get the steering stabilizer for it as well, it helps.
Make sure you have extra money set aside when doing this, you never know what you may find needs replacing in the front end while your doing all this.