No brainer mate, keep what you have got.

The bmw is a nice car but a 318 is nothing special and with basic spec even less appealing. Add to that they are turd in the snow and winter is a breath away, don't snow much but admittedly but when it does it can be shite.

Rear wheel drive fun people scream about, well maybe on something with fire in it's belly but I had a 123d M sport couple and to be honest you very rarely noticed the difference. I now have a scirocco GT and it's really nice and easy to drive.