another point is that when it comes to changing car, you inevitably have to get something with more power, otherwise you will question your own sexual orientation.
youll have to go some to better an M5 lol
its a great idea but its a big ol car, youd look a bit silly at 17 getting in and out of one. the petrol costs will be immense. the learning curve will be immense, get it wrong and 340bhp will have you dead in no time.
i personally wouldnt trust a 17yo in a 340bhp car. most of them have trouble judging braking distances when travelling fast in a 1.1 fiesta. in a 340bhp big saloon it will be difficult without the experiance etc etc
i wouldnt recommend it, unless you have cash to burn