Tahoe performance

I have a 99' Tahoe and would like a little more performace out of it. I have looked into Hypertechs power programer with claims 20hp. That is $300 for not a lot of power. I have seen these "chips" that plug into the IAT sensor they cost $6 and claim about 20hp. So does any one know about these IAT sensors? I am planing on doing a cat back and a K+N but what Should I do about the computer programing?

I think those "Chips" are just resistors that are put in-line. They fool the PCM into thinking you are taking in cooler air.

20HP is BS...