man, if all hes got is a Dummy tuner, youll walk his dog, even in 2wd. my megacab had a Dummy, with a turbo and dual disc, in 2wd VS my wifes 2wd chevy. when i got to 6th gear, and with the chevy in the heavy tow tune, that thing blew by me like i was standing still!!
Dummy was on SW5 and the tow tune was maybe a 60hp tune.
also had another instance, kid in an 06 Cummins with a Dummy, AD150, and a couple other things done to it, he took me from a dig, barely, but i quickly caught up and left him no problem. that was in the same heavy tow tune. i started messing with him, id let him catch up just about the front tire, then id give it a little fuel, and leave him to about 3 car lengths, then let him catch up again and start it over hahaha. he was pretty mad, so to keep him from crying, i quit and went on about my business.