I currently have a '94 530i with the V8 engine. It has been a great car and is still running strong. I have been thinking about getting a 540i around the 2003-2004 model year. It appears that one can be had with low miles (say, less than 60,000) for around $18k. This would appear to be a bargain. Is there something I should know about the 540 series? Are they trouble prone?