I wouldn't bother then mate to be honest. I think the cams alone are about the 1500 quid mark. To do the whole valve train probably about the same again. You might get someone to give it a port and polish within your budget.. but to really get the best use from any of those mods you want to be aiming for big power from some huge turbo, so you'd need to do bottom end too... gearbox, diff, clutch, probably axles, brakes...and on and on and on.
You could spend that dollar on something better if you're after more performance - headwork alone is a bit oldskool and doesn't give massive gains on our engines.