Dad is looking at an '02 1 ton 4x4 dually CC long bed with the Dmax and 6 spd manual. I know that the new Dmax's are detuned for the manual only.....is that the same box in an '02? Is this a reliable box that can handle heavy towing? In OD? How about if the dmax has a chip? I am not familiar with the new manuals in the chevs....thanks.