You'd be surprised actually. I have a massive folder of receipts and service history, including regular services. Why the oils were wrong, and over filled, im not sure, but it was regularly changed.
Its also had a lot of other work like suspension, bushes, brakes etc.
Other than the vanos, there is really nothing that is more than cosmetic. Even then the vanos is just noise (and maybe a little loss of power), and in terms of noise its pretty minor (going from the tube of you videos of noisy vanos's).
E: Yes, Castrol Syntrax Limited Slip 75W140 is what BMW specs the plate type LSD for, and its what i have used. Its a great fluid, im impressed already. I think BMW sells it, but repco and BNT dont. I got mine from work, which was Mercedes, as its also used in the latest AMG diffs.