http://www.quaife.co.uk/shop/search/...xonomy%253A619

have a read here, the 69G will do 750hp

I ran a 5 speed h pattern T9 dog box for ages in a 2wd sierra rally car.

ive even run a 5 speed quaife clubman for about 6 rallies, they only rate them for about 175hp.

HP is not your concern, especially with a turbo rally car, torque should be what your looking at, if your making near 500ft/lb at 3000rpm then your gonna kil alot of gearboxes lol