Do performance chips work?

[1COOLH3]

Chips from reputable companies such as Hypertech can make a noticeable improvement but don't fall the cheap pieces of crap on ebay.

Newer GM vehicles no longer have replaceable chips- they now have PCM's (powertrain control modules) and the only way to modify them is with a Power Programer which cost about $400. Hypertech doesn't have one for the H3 yet but I've heard they are working on one. I wouldn't expect any huge gains on the H3 - there is only so much you can do with a 5 cylinder but even a little bit would help.