I am looking to buy a 2001 to 2003 530i or 540i. First what are the major difference between the 530 and 540? Also what can I expect regarding longevity, maintainence, major reparis etc. This will be my first BWM so I really do not know much and have no history. Although I have always loved the style of the cars and have heard of there great reliability. I have a friend who has a 7 series and I have not asked him too many questions, I also do not know how those compare to a 5 series.