It depends on the tyres, driving style, alignment and probably other factors I haven't considered. For me, I got 20k miles out of a set of 4 by rotating them every 5k miles or so. That was for Pirelli 19s. I replaced them with Michelins at a cost of £720 and they are proving to be a much better tyre, if I can get the same mileage out of them I'll be very pleased. Servicing is very reasonable and economy I think excellent but would of course depend on many factors. My long term average at the moment is 35mpg, 30+ on steady commuting, 40-45 on a good long motorway run, up to 50 in the right (read boring..) circumstances. The GTI is not an expensive car to own but very rewarding