Things to look out for when buying a 540i
1) Has the PCV on the back of the manifold been replaced? (they go at about 175-200k km) cost R1400
2) Is the radiator and expansion tank new? ( A sore point on these cars, an all black expansion tank is a replacement and is safe) A fact of life with a 540, big engine stresses the cooling system and ALL of them have been through several radiators, it's normal and cooling parts are moderatley cheap
3) Are the O2 sensors good, they only last 160K Km and are damn expensive, about R3000 each Post 98 cars take four of them, pre 98 take two.
4) Does the engine idle smoothly and make almost no noise whilst idling? If not walk away immediately.
5) Almost all E39's will have dead pixels on the cluster, do not let this stop you from buying a car, affects even the best of them. a DIY fix
6) Zero warning lights and errors will indicate a good well looked after car, they complain very quickly if ignored.
7) if the car is a Steptronic take it for a good drive to make sure the transmission is behaving they last 250K Km max whilst the engine lasts forever
8) If the fuel consumption on the OBC is over 16L/100Km be suspect. It's a big engine but when driven normaly will return between 11 and 13L/100km
9) A full service history at a stealership in SA does not particularly mean the car has had the best service, so take it with a pinch of salt. There are some very good independant BMW service centres around.
For R75 k you can buy a 540i that sold for over half a million when it was new, there is probably no better bang for buck these days than a good clean E39 540i
Good luck hunting one down