Tough choice in getting my new car with my current budget?

I have a dilemma here of either spending approx.$80000 buying a 2011 BMW 535i xdrive and keeping it for 8 years or spending half that amount ($40000 approx.) on a 2011 Acura TSX and get to drive another new car in 4 years' time. Any suggestion? This is even tougher than deciding whether to get married or not.......