Yep buy one that's been done, and done well.

But as said, the higher the BHP the more £££ your going to be spending as things will go pop on you.

You should be able to use a 250bhp 2.0 zetec turbo lump without to much stress and hassle, so long as all the other items have been upgraded to match, clutch, box, brakes etc.

Only trouble is, is that this engine mod is relatively new so there aren't going to be loads out there and they won't be cheap, a really well done CVH lump with all the trimming, minty body work and sorted interior is a good option and will leave plenty of change from £6k, plus there are loads out there for you to pick at.

Once you own a turbo'd motor it becomes very hard to go back to a normally aspirated car, you'll love it.