Christain - some questions?

What the most bolt on hp you will see and still be a nice car eg gt30/manifold/injectors etc or what is the real max hp you have to go internal?
Do you need to change out the std HG or can they take it?
Do you remap the original ecus?

What do the std gearboxes,clutches and diffs last up to if giving the car regular abuse? E.g cossie rear diffs can get unhappy 360 odd hp but T5 boxes seems to take 500hp for a good little while etc.

Cheers

Martin