Electric chairs? sounds a bit dangerous lol.Another Scotland member here. I changed from a Golf GTI, probably with the same engine as your TT. MPG is far worse, probably as much as 10 mpg less. Fuel tank is very small and probably get over 100 miles less than GTI.
But it is a far more fun car, and the exhaust encourages you to rev it out and make it bang haha.
Tyres are fine, I do drive to the conditions however. The LSD shudder is a weird thing on full lock. Would it make me spend an extra £600 on Michelin's, I'm not sure. If anything, I'd downgrade to lightweight 18s with bigger sidewalls.
Stereo pretty average, and a step down from a VAG interior. However, you have many options like heated seats, steering wheel, electric chairs, reverse cameras.