I have a 2004 manual G35 with HKS high flow titanium exhaust and a couple other small engine mods and I was thinking about getting headers, test pipes, and possibly forced induction in the future. I already bought a clutch that can handle 500 ft/lbs of torque and I was wondering how much the stock transmission can handle in terms of torque and horsepower.

 

Most likely more than you'll ever put through it.