OK, had a few genuine enquiries on this now, thanks to those who expressed an interest.
This post is intended as a guide for costs on the conversion, it can go either way depending on your requirements
Costs wise is very dependant on what power level you wanted, provided your engine is in good working order with good compression a low boost ( up to 7.5psi) conversion will put out a safe reliable 250 lbs/ft 240+ bhp all day every day.
If I had to supply all the components and fabricate the charge pipes etc from scratch you'll be looking at Ԛ£1500- Ԛ£2200 supplied and fitted as a drive in/out conversion, timescale would be approx 2 weeks from start to finish, depending again on how hot you want to go.
Higher boost on the stock bottom end is possible but larger injectors will be required, they'll increase costs by Ԛ£300, max the stock enginme will take is 14 psi, longevity would be compromised if you were a heavy right foot user.
cost per bhp is prety good, lets compare with some other popular upgrades.
Strip head, new internals and perfoprmance cam, refit and chip to suit,
Costs cԚ£600 as a DIY project, expect 190 bhp
maximum = Ԛ£31.57 per bhp gained
Fit turbo for low boost high torque conversion, expect 240 bhp
minimum
cost c Ԛ£1500 = Ԛ£27.73 per bhp gain
Lets not get carried away with peak figures, the linear torque response with the turbo makes the car very easy to drive without needing to work the engine hard all the time, indeed midrange urge is something to

at.
HTH