You might be best off selling it and getting a 2.8 V6 4motion instead if you want to make a sleeper Golf. You'll have the benefit of a better engine that's more supported in terms of modifications and forced induction but also have the 4 wheel drive system which will aid traction massively if going big power.
Saying that, a 2.8 V6 engine would fit into a V5 Golf bay, and you could still turbo it but not have the weight penalty of the 4motion system. You could also use the gearbox from the 4motion and blank of the transfer box (thus making it a 6 speed, front wheel drive car).
Hope this helps mate, I'm currently ripping apart a V5 Golf so give me a shout if you want any more help.
