I think to run at 500 and use all of it is not cheap, std t5 and a atlas is on borrowed time with 500bhp, my Cortina with a t34 at 390 spins in third on 245 cr500's so bigger wheels & rubber to get it down.


Engine wise for 500 your looking a 10 studs and cp pistons, head work, a cam or cams, inlet, 83lbs injectors, big intercooler, decent boost control and ideally after market ecu.


Then a high spec t38 or gt30 unless you got the budget for a BW and manifold.