Golf GTI: used car buying guide - What are the running costs?
This GTI uses a turbocharged version of VW's 2.0-litre direct injection FSI petrol engine, so it's designed to give respectable fuel economy as well as brisk performance. Official average economy is 34.8mpg, but drive with a heavy right foot and that will drop noticeably. Insuring a GTI isn't going to be cheap, because it sits in group 17.
Servicing costs are higher than for the standard Golf, but aren't excessive. There are plenty of independent garages who specialise in the GTI, and they're good value for cars outside the manufacturer's warranty period.
Despite the car's reliability, a poorly maintained example could give you no end of problems, so bear that in might when looking at very cheap cars. The GTI depreciates slower than most of its rivals, so you shouldn't lose too much when you come to sell it.