torque/power limit in 02Q

Getting closer to buttoning up my driveline and wondering if any of the mk5/6 cars are having with bigger power in the 6-speeds. I'm on the fence if I want to open my gear box now as I know that will quickly escalate into diffs, etc. I also don't want to put it in to have it come out again because of something I could have done when it was out already.

power goals are north of 250WHP.