Depending on who answers you will get a different response, if you plan on off-roading some will suggest the 5100's. I don't off-road, just wanted a more aggressive look so I went with the ready lift 2.5" leveling kit. Shortly after I got my Toyo Open Country AT's 285/75/18's and then I added the 1.5" rear blocks. What ever route you decide to go do yourself a favor and get a diff drop, cheap insurance.
Here's a pic of my truck with just the leveling kit and one with the rear blocks added.
Here's a pic of my truck with just the leveling kit and one with the rear blocks added.

