I had three times normal than usual oil consumption with my 325xi. First time it was the oil filter housing leaking, second time it was the oil pan leaking, the third time it was the CCV not working as it should. After each time I had fixed one of those, I was back to not even needing to add oil in between CBC oil changes.
If you decide to change the starter Fcpeuro has brand new Bosch OEM for $140 on discount with no core return needed. You will need a new aluminum alternator bolt set too.
And you will need a e-torx wrench. Regular e-torx sockets on ratchet's don't fit in between flywheel housing and firewall.
I would rather have paid the $140 extra on the starter and replaced it when I had done the CCV replacement. It is not fun doing that job of removing the intake manifold with the CCV hoses and wires not even visible, twice. Plus those hoses that are likely to break will break unless you are very careful and two of them come close to the price of a starter. (If you don't break them return the new ones).
And then there is the issue of towing the car if starter decided to die not at home and you either have an automatic, or weren't lucky enough to have parked on a hill or finding people to push your car while you pop the clutch to start the engine.
Everyone has their own priorities. It comes down to opportunity costs, expected values, risk management and all that …
