Originally Posted By: MCompact
It's a chain; the last BMW engine sold in the US with a timing belt was the M20 "small" six. VANOS simply retards or advances the camshafts relative to the crankshaft.
'90's motors only, aka 'single vanos'. Once the 2000's hit, they went on to dual vanos, variably controlling both cams p to 60* in some cars with the PCM. The N52 in OP's car is technically a dual vanos motor, but it's also valvetronic. Vanos adjusters on these engines are nothing like the older engines, and to date they're rarely a problem. You'll replace multiple vanos solenoids on an n52 before you have to replace a vanos adjuster.