I'm in the exact same boat myself. My beloved 328 has just over 41k miles, is 4 years old and I only have 11 payments left. I think I'm going to hang on to it a while longer but don't know how much longer I'll be able to deny that new car pull. I've mulled the prospect of leasing a new Bimmer next year and simply holding on to the 328 as long as I can. I guess we'll see though..
Current: 2015 Audi A6 3.0T
Gone but never forgotten: 2009 E90 LCI M Sport