That's I get for skimming the posts.As someone mentioned before, 5.2 swap would be a lot cheaper for those kind of ponies. He only want 20 hp more. What I did to mine was relatively cheap and satisfied my desires for the truck.
20 should be pretty easy to get. I know some that just retro fitted a bigger throttle body, added a super chip, got 15 more horse. Yes he actually put it on a dyno. That being said I'd be surprised if you could find a new chip.