The manufacturer's warranty on my 2008 1.6 petrol Ford Focus ends in a few months. It's got roughly 30,000 miles on the clock. As I see it I can trade it in or keep it and run it into the ground. Problem is, I have no idea of a trade-in value to aim for or if there's a new or nearly-new option out there I can trade it in for that will make some modicum of financial sense. I'd ideally like to switch to a diesel and get some more grunt under the bonnet without blowing out the economy.