As a mk5 gti owner I'd suggest that, or if you can find one, a ED30 version as it has the bigger k04 turbo and is 240bhp vs 200bhp.
A remap at RTech will see those figures jump from 200bhp to 230-250bhp and the ko4 from 240bhp to 290-310bhp. Remap would be around the £370-400 mark I think, and if you get the DSG which I recommend it'll need a map too at around £170.
Lots of mods out there for them, great scene, interiors are a lot nicer than some of the similar aged hot hatches. Performance and mpg sit in the middle of the band for hot hatches of the age but the mods and interior swayed it for me, plus coming from a Corrado g60
Mine's slightly modified, average 26mpg on a spirited commute, 20mpg on a really fast run but general commute I'm getting 34-38mpg over a 26 mile mixed journey. Keeps up with generally faster cars and is just great fun to drive