If you fancy buying a BMW E39 5 series then this info could help.
When it comes to spec the 1996 onwards E39 came with lots of extras as standard. Things such as traction control and
air bags were fitted as standard. Electronic suspension and electric mirrors were fitted on practically all models. However the spec to aim for is the SE trim level. You can be assured of on=board computer, alloy wheels, air-con or sunroof. When buying
second-hand look for as many extras as possible as some were rather expensive options to start with. The more extras such as Sat Nav, leather and parking aids the more desirable but try not to pay over the odds for them.
If you want the ultimate family wagon, then take a look at the touring model which is a very good estate car and a very luxury holdall. You may also have to check for wear on suspension and brakes as these can be heavily used. If you are thinking of reselling it is best to avoid the foggy metallic red colour. The best colours that should resell easier are silvers and the dark metallic blues and greens. Black holds a certain presence as well. A high mileages BMW E39 5 series should not cause any problems as the build quality is very good on these cars and high mileage examples run just as good as brand new. Therefore it is wise to check for previous MOTs and service history as clocking one of these cars could easily be done and you wouldn't sus by looking or driving that a higher mileage had been done.
Do the standard checks if you think things are too good to be true such as pedal rubbers and seat facing for excessive wear compared to the mileage given. If you purchase a 1996 to March 1998 520i, 523i and 528i model beware that some of them suffered with what is known as the NIkasil problem. These cars suffered from excessive bore wear as they got attacked by sulphur from the fuel. A lot of these cars were called back and fixed under warranty, however if the car you test drive suffers from poor running Smokey exhaust or uneven idling then this could be the problem. other checks on the running gear should be pads and discs as they can wear as 5 series are generally heavy on brakes. You may find the airbag light comes on and stays on. Two causes, one is the wiring which goes to the pre-tensioner. Should be a fairly low cost fix, The other cause could be the passenger occupancy mat which senses when someone is sitting on it. This is a more expensive job to repair though. As there are lots of electrical items to check on these cars it is wise to sit in the car and check everything works properly.
One of the problems that has occurred with my own BMW 5 series E39 on a 1999 plate is the failure of the lighting control unit. This caused one of the full beam headlights to stay on permanently even when the ignition and light switches were switched off. To overcome this problem and avoid buying a brand new light control unit, I opted for disconnecting the wiring which led to that light that stayed on and running a new wire from the light that worked properly over to the light that was not working. Hey presto saved a couple of hundred pounds.