Best place for tunes for 2007 6.0L Suburban

Not sure which forum would be best to post this.

I know asking a question like that is like asking which is the best religion, but I'm not much into electronic gasoline powered cars (either old school gasoline, or electronic diesels). My boss wants to find out the best way to get the most power out of his 2007 Suburban with a 6.0L. He has already added exhaust headers, and is currently running a Hypertech programmer.

Regards,
Michael Pliska
ISSPRO Engineering Manager