"The 2012 BMW 750 has the most overall complaints, & we also rate 2012 as the worst model year ranked on several factors such as repair cost & average mileage when problems occur. The most-reported problem is with the 2006 BMW 750 for white smoke due to valve seal failure." (Carcomplaints.com)

"The 2008 BMW 535 has the most overall complaints, & we also rate 2008 as the worst model year ranked on several factors such as repair cost & average mileage when problems occur. The most-reported problem is also with the 2008 BMW 535 for water pump failure."

Seems like EVERYTHING is a problems with those BMWs. Electronics, Engine problems, you name it! Auto transmissions are somewhat weak as well. I would not get one or keep one.

I don’t know much about that specific model. In the same generation, I drove a 2007 X5. 

After about 160k miles, these are the things I had to deal with:

- valve cover gasket leak

- broken PCV valve which requires the whole valve cover to be replaced. 

- DISA broken, made of plastic.

- misfires, charged out coils and spark plugs.

- replaced thermostat

- replaced AC compressor

The engine and transmissions itself is amazing. It just cost an arm and a leg to maintain.

Well, … that car - E65, in general - from an early two-thousands (2001-2008) was a marvel in electronics, … feature by feature, years ahead of anything else!

Today, … it is a dinosaur, … technologically speaking. Not only that, all that technology was/is just perhaps, most unreliable in history of the world, beside being outright superseded. Who wants that? Today?

Anyway, … you ask "common problems"? Everything! You name it, … it most likely needed few repetitive repairs already! And most likely still does, …

Best,

F.S.

About the only thing you'll find more expensive than a cheap BMW would be a cheap Jaguar or Land Rover.