£2k on a ABF will not get you more power than a 1.8T
Simples
Well ok yes may get away with a home brewed turbo conversion but how long would it last.
Are you sure??
Last fine. over 10k since build and no problems with engine.
With respect you know what you are doing etc and yours is a high standard of build, not going to be cheap or easy when you factor in all the extras etc.
Nothing good is ever easy. There are way of doing things cheaper.
Toyotec on CGTI spent alot on a lightend, balanced bottom end then the mains spun due the the wrong bearings being supplied. All replaced with an used AGG crank and reused head bolts and reliably puts out 315PS.
Not that its the ideal way, but its possible to do some shortcuts to get what you want.

ie you dont need to lighten flywheel, replace rings, bearings, oil pump, use ARP head studs etc