Does anyone have experience with an Xterra as a toad four-down? I'd love to buy an xterra as my personal vehicle and as a toad for our motorhome, but seem to get mixed messages about:

Transmission: Manual vs Automatic?
Drivetrain: 4x4 vs. 4x2?
Warranty: Will it be void if towed 4 down?
Fluid Circulation: Is it necessary to stop and
exercise it every 500 miles?