The only prohibitive I think of is BMW maintenance costs.
If you do your own fluid changes and valve checks, it's not a problem.
Rarely do the late boxer BMW's need a valve adjustment, but if they do they are $$$ thru the dealership.
A little tedious but you can do your own valve adjustments and save hundreds of dollars.
Thru 09 the valves are screw adjustment type.
10- 13 they are shim-over type (actually easier than the screw type IMHO)
Wet heads are shim under cam. (pull the cams. scary procedure but you can to it. cams are gear driven and you don't have to mess with a drive chain.)
That said, the 2010 and up boxers rarely need a valve adjustment. I put 120k miles on a camhead RT and it was never out of adjustment and never needed work
My 1200R had 35k and never needed adjustment.
My 1200RS wethead has 32k on it and doesn't need adjustment.
My new 1250 RT had 23k on it and doesn't need it.
So unless something actually breaks the maintenance costs shouldn't scare you and procedures are actually quite fun if you do them yourself.
Grab something like the GS911 code reader and the electronic maintenance can be doe on your own too.
https://www.hexcode.co.za/
SS