[Dual K20s]

IMO it's better to buy a stock truck. Power mods have the potential for more abuse to the engine and drivetrain.
Plus it's fun to do the mods yourself.
Definitely never pay extra for mods on a used truck.

Great advise. The more that's been done to the truck the more chance its been abused and seen a lot of heat.

It may still be a very good deal, in the end its your call.