Depends on your taste. If you like high compression, high revs, the G-Limited is a good pick. If you like turbos, the GT is a good pick. They're both great vehicles, it all depends on which flavor you like.
the g-limited definitely has more horsepower than the GT non turbos, depending on the generation it could be as much as 55-60 hp difference. i think the g-limiteds were all 200 hp while the 2.0 non turbos were from ~140-180 (the hp went up the longer they were produced)
OK, I think the UK spec GT non-turbo was the 3S-GE, 156 or 175 hp depending on year, while the G-Limiteds you're seeing will be private imports, and are the exact same thing. What you'll need to watch for is the 3S-FE powered cars, which are very slow. You should probably be asking on http://www.mr2oc.co.uk/ though as they would know the specs for your market better.