I've never run into a gti-6 before but I have had a run with my mate's alfa 147gta after he was hyping up his car alot so he asked me to stop being a wuss and get alongside him so I did, was pretty even till 3rd at the top end of 3rd I just started pulling away from him, pretty much game over and Im only pushing a pathetic 240+ bhp - it's a daily student shopping car. I've not spent much to get to the power I'm at now, it's a cheap and cheerful car to tune, although I can't speak for the peugeot's 2.0L 16v engine I doubt that you'll be able to get as much power out of that engine for the same amount of money on mods. So for me it would have to be the 1.8t, if you must get a french car the renault megane r26 is quite rapid, I've been on a few cruises with a mapped up r26 and it pulled very nicely.