I drove both a S600 pre facelift 390 bhp and the s600 TT 500 Bhp.
The difference is massive. Also the interior is so much better in the s600 TT, but maybe its because the one i drove and now own is exclusive leather.
Thing is with these motors when things go wrong its not always it costs alot, but finding people who can work on it and not create more problems.
I have spent close to 5k on mine in last 6 months. I spoke to a guy who deals alot with s600 and he said 2 types of mileage areas to watch for big bills on a s600 is
60k to 80k and then again 130k to 150k.
apparently that is when most of the things like coil packs, suspension, cats, etc start need replacing. I think what you get is 2nd owner gets 20k miles for 4k repair bills and passes on.
If you look around then you can get good deals on fixes.]
Mine had new turbo for £500 quid instead of 2.2k and also 4 new sport cats for 900 instead of one bank for 1.2k
I drove a new s600 08 plate and its same performance as mine 03 plate.
Interior is nicer in newer one, but the actually drive is about the same.
The difference with a TT S600 and a normal S600 pre facelift is massive.