When us old school blokes used to talk about doing a 'tune-up' we'd be setting valve clearances, cleaning and adjusting points and plug gaps, and adjusting the idle speed and accelerator pump throw.
'Servicing' the car involves changing oil, filters and plugs etc. - routine maintenance. Then there is repairs such as replacing parts, gasketsand hoses, and more major surgery such as engine and transmission rebuilds.
So with O2 sensors and electronic engine management systems, platinum-tipped 100K spark plugs, and coil-pack ignition systems, there is nothing the average punter can do to 'tune up' these cars.
However with a Bentley manual and additional information from sources such as this forum and E38.org, routine maintenance and even more extensive repairs are within the reach of reasonably intelligent BMW owners in possession of a good tool kit.
So the answer is yes / no / maybe, depending on what the actual intent of the question was.