As for the tranny issue, they CAN hold the power if you don't drop all the power on it all at once, @ 500whp you are going to have massive traction issues so you would have to wait till your through 1st/2nd before you give it all the power anyway. Besides pull a part has cheap trannies all day for 50-100, My father was a junkyard gear head, destroy a motor or tranny? no worries theres another one in the junkyard to replace it for cheap!
08 Infiniti G37s 6speed (The Daily)
Stillen Cold Air Intake, Z1 Plenum Power Mod, Z1 Headers, Z1 Test Pipe, OBX (Ark) Exhaust, Up-Rev Osiris Engine Management (Tuned at Z1), 20x9" 20x10" Str Racing Concave Staggered Rims, SPC Camber kit, Tein H Techs Springs
I've seen your name around, I meant no disrespect, I promise 
Any thoughts on upgrades besides PAR gearsets?