WHat is so special about leather? Cold in the winter, fries you legs in the summer! dang near as bad as vinyl! The only thing nice about leather from the get go, is the heated seats.
Reality is, your current 6.0 gas is everybit as capable as a dmax. Other than less HP. And the HP difference is pretty minor frankly! Compared to days of yor, when one could get a 105HP motor up to low 200hp in a truck like you have! a low to mid 300hp motor vs a mid to high 300 hp motor, nothing worry about. Yeah the diesel has more torque. BUT the 6l90e has a 4.1 first gear with a 2.05 tc, vs the dmax with a 3.1 first gear, and a 1.73tc. At the end of the day, the gas rig might actually have more torque to the rear wheels than the dmax in first gear!
Marty