The way I see it is if you are happy staying with the stock ecu and fuel system buy a steel turbined ct20b, its all the turbo you will need for ~275rwhp. Add some HKS 264s and an aftermarket sidemount I/C and I'd guesstimate you could max out the stock fuel system with 1 bar of boost.
If somehow you want more than that on the road (which will still see off 95% cars on the road) mortgage your house, sell your grandma, whatever, it aint gonna be cheap.
For more power you need a decent turbo, with that decent turbo comes the need for better cooling, then more fuel, then you need something to run the new fuelling, then you will need a better clutch...the costs will mount up quickly. You then have to weigh up HOW much power do you want, because either way 300rwhp isnt going to be much cheaper than 350rwhp.
If you are down this way or in the Marlborough area in a few weeks time when I've fitted my new clutch, I'll take you for a run on my test road
