The superchip will void the engine warranty, which is the only part of the warranty that's actually worth anything. The suspension warranty is short, anyway.

But that's only if the dealership finds out. It's easy to install/uninstall chip upgrades, and re-flashes are mostly invisible to diagnostic equipment.

Personally, the D-max isn't really lacking in power. The Hi-Lux's extra horses are only noticeable above 120 km/h. From 0-80 km/h, the automatic transmission of the 3.0 D4D is kind of sluggish, and there's some turbo lag in traffic... so short of a peel-out drag race, your boss won't notice much difference between the two... as both can hit high speeds on highway runs to N.E. (which, I guess, is probably why he wants a powerful truck... )

Tell your boss to forget the power, test drive both and see which he likes better. I think the Hi-Lux handles better, but the D-Max has a slightly (very slightly) better ride and car-like controls. If he's going to sit in the back, medyo cramped pa rin ang D-Max compared to the Toyota.