firstly, don't put too much stock in TopGear's thread. 240rwbhp is simply impossible from 330cc injectors. 170rwbhp and they'd be well and truly maxed out. its a bit unclear if he fitted the 440cc injectors before that or after, but they'd be maxed at about 220rwbhp. Its reasonably unlikey that the stock gearbox or tailshaft would stand up to one dyno run at that power. There was no mention of clutches in that thread either, and both the old A12 turbos I built had issues holding in 3rd gear on uprated clutches. And we would have been making about half what they claimed.

I've used an S13 T25 before. worked well on an A12. Would make enough boost at 60kph in 4th up hills that you wouldn't have to downshift, for example.
A mate used to use stock WRX turbos on his Suzuki Swift with very good results too.