So unfortunately timing chains on BMWs are getting harder and harder to do. For the B/S58 they moved all the vanos hardware to the back so if you need to do a timing chain its an engine out service. I would say this is a lot for that year X3 but for a modern car this isn’t out of the world price wise considering how much labor it is just to get to the chain, maybe they are going off that and quoting you what it would cost for a much newer car.
I’ve worked as an SA at a BMW dealership. The only thing I can say is if you get the manual please respect the hell out of that clutch. The amount of people I’ve seen come in with 5-10k miles with clutches in tatters is astounding.
Have you tried calling around yet to find an allocation? In my area M3’s are back ordered for a few allocations meaning those will need to be filled or that customer to back out before you can order one. I actually went for M4 Comp because M3 would of likely taken an extra 6+ months at least, if not longer.
Is there any way to prevent the update? Can I just not install it. Weridly my M4 Comp got an update like last week but it wasn’t idrive 8.5, it just updated it from the March build to the July one but im still somehow on idrive 8.