The mk6 I take it? It is a great car, my boyfriend had one last year but he sold it while he could still get money for it as it was nearing 65,000. The only problem (which others may shed some light on) is the gearbox can get really stiff, nothing major to worry about as most STs get it with higher miles or... if they've been thrashed! I believe it's just to do with the gear linkage which if you keep it well oiled you should be alright.
Apart from that I would say wait till the new ST comes out as the prices of the mk6 will drop (as most have already) that's just my opinion on what I would do so I wouldn't loose alot of money from it. But hey if you can afford it on you go
I would I just can't afford the insurance