Hopefully someone will be able to help you, as I've never driven a GTi turbo. I understand they have less power on "paper" but are in actually fact pretty close. I would of thought the Golf would be more tuneable given that it has a turbo.
As for chassis handling etc, I suspect a good clean ST170 would show it the way home.


A lot depends on what you want from a car really, the VAG scene is pretty big, as is the Ford family, reliability of both cars depends on how well they've been treated, and the costs of running each will be around the same I recon.



If you are looking at the ST170, then please check for rust on the inner rear arches, as it's a hidden spot for it. Also check the IMRC is working, located on the bulk head/fire wall, as these often fail. Fuel pumps are a known issue and will cause fuel starvation on low fuel level running, like tiny flat spots and miss fires. The dual mass flywheel is also an issue on the ST, but mine has been making a rattling noise for 5+ years, and still hasn't let go or slipped lol.