If you plan on nothing more than an intake and cat back in mods, the BDGT is the best bang for the buck. You can get them used for around $275 shipped.
If you shop around, around $330 new.
If you plan on going with headers or cams, go ahead and get UpRev. Cost is $500 and you get 3-etunes to use at a later time. Also, the package comes with Cipher, which is a diagnostics and data logging program. UpRev is by far the best, because it is a custom tune for your truck.