my mate runs 400bhp on standard gearbox.hes hardly ever done a mental launch though .. never needed to when hes racing it lol and i know of another saff that ran 420bhp on a standard gearbox. it blew the box after 6 months of abuse . dont do launches on it and it should be ok both were t34 cars . if you have a t4 then id run good amount of boost to make up for the lag and run a quickshift with a uprated box[jack it into gears and rev it up for it to boost ] otherwise i think a t34 car would be slight quicker untill a long stretch.. its just my opinion