Loftys pretty much right - if you were going to put a 5 or 21 turbo in it, you might as well have bought an RT rather than a valver. Ive done most of the mods that are do-able on my 16v, and to be honest, there is very little you can do to *seriously* improve the power output with filters, exhausts etc. Head and cam work has made mine noticeably pokier though. However, the 2.0 lump seems to be very strong in standard form and with head and cam work, you will see solid results.
I would suggest a 2.0 bottom end, or entire lump. The only other alternatives for power you can really feel are a turbo (£3k at BB Tuning?), throttle body conversion (Weber Alpha kit is around £1600 although you do get the full engine management as well), head and cam work runs to around £1500 at Hill Power, then theres nitrous, great for occasional blasts and quarter miling, but dont kid yourself its gonna come cheap. Assuming youre not gonna get the bits you need out of an old skip, youll need at least an 11lb bottle, 50 jets will go straight on but if youre aiming for more than 60 Id say you need a controller. Could be anything up to a grand if youre not fitting it yourself. Then theres the cost of the gas, currently £5.50 per lb at my dealer. Like I say, its a good kick in the pants, excellent for 1/4 miling and those moments when you just have to get in front and surprise people. Not good if you want a generally faster car.
