While the price is outrageous, there are some sick parts on that car. Eibach R2 coilovers, full Currie built 9" rear end, watts link/chassis bracing, giant wide wheels, liquid cooled KB blower, built bottom end, etc. I'd say $60-70k wouldn't be out of the realm of possibility if you were starting with a stock GT500 and doing all the work yourself, but $150k just for the upgrade and you have to supply the $60k GT500? Screw that noise.