if you set the billys to 2.5 with the tsb, you're going to be nose high in the front. you're best bet is to order billy 5100s from downsouthmotorsports
(all 4) set them @ you're desired height and put an aal (add a leaf for tsb from toytec
that would give you the best and quality lift for your money. also, be aware of potential issues with raising your truck 2.5", search driveline shudder. it doesn't happen to everyone, but it does happen and a possibility on your truck. you'll never know until you get the lift installed, things that correct this are alignment, shims, carrier drop, and/or swaybar relocate kits. all of those that I mentioned are available on the toytec website. if you get shims, you need longer ubolts as the stock ones barely clear with the aal and shims per darrick @ toytec.
ToyTec AAL for TSB
3 degree zinc axle shims
The Drive Shaft Carrier Bearing Kit
I've done much research and reading on this forum about this as I want to lift my truck soon.