I am considering a 1995 540 purchase. I have given up looking for reasonable priced 325-328is and find the 5 series to be a better deal considering original new prices. How are the 540's on gas and maintenance compaired to 3 series. I currently own a 1986 635csi which I use as good weather driver. Is the 540 a money pit to maintain? I do most maintenance on my 635csi and don't think it is that costly in parts.