We dont love bm's cause they economical... we love the sound, the looks, the fact that we can give Fix Or Repair Daily grief, while having many hours ourselves under the car with a gearbox on your chest, repairing breaks etc. How are you going to know you car intimately without spending time and money on her (and in this case a lot of fuel) but the far more economical V12 5l is definitely the way to go. after all I only filled the 90l tank twice in two day. (well she's still full, for now)
on the subject of an e60 m5, personally great engineering but I really don't like the looks :-(. dont get me wrong amazing car, just does not get me too excited on the looks department. theirs a m5 99 model for 22k, that's a pretty car.