Hello, I've had my 320d M sport now since last year, and I'm impressed with it. It's a 2009 LCi model with Start/Stop function and it drives like a dream, as the last post said on here, drive it sensible the your get 50-55 mpg, drive it hard and fast then your looking around the 30's mpg. There good on long runs, comfortable and well equipped. Yes speakers do let it down, but there is a Tweeter modification you can get which involves replacing the inner door trim which houses the new tweeter. (I've not done it so not sure what the outcome is) As for servicing them, well there pretty cheap enough, and if you know what your doing then even better. I've just done a complete Front and Back brake pad change including sensors for £80. Rear tyres do wear a bit as they would for a Rear wheel drive car. I managed to bag a pair of part worms with 5mm tread left for £60 You asked about modifications, all I did was stuck a K&N filer on mine and some diesel injector cleaner in the fuel tank and I really noticed the difference. Mines now on 98k and I'm selling it to get a 5 series, but it's been one of the best/fun cars I've had in a long time. Good luck.