[KennyP]

Seems you have been lucky with maintenance and repairs. Only basic servicing and a few things that are well known to go bad on bmw-s like those oil filter housing gaskets and valvecover gaskets...

I have had to do a bit more than that. Imported my 2009 35i from Germany in the spring of 2016. Its going to be 8 years of ownership in a few months.

I also have done almost all those things you listed...
all the regular maintenance: oil, brakes, spark plugs, battery
Oil filter housing gaskets
New original valvecover with gasket and pcv
New set of ignition coils
DCT service and diff oil change.
i have replaced all bmw badges on the car, wheel center badges actually replaced twice....

Im suprised you havent done anything to the suspension... not even a single stabilizer bar endlink...

I basically have done almost all the suspension repairs you could think of:

front adaptive shocks failed... went to a kw v3 suspension setup.
replaced all front control arms with m3 arms... one went bad so decided to do them all...
replaced tie rods once..
replaced front stabilizer end links twice
replaced front shock top mounts
replaced front wheel bearings twice
replaced rear trailingarm bushings and balljoints once
replaced rear wheel bearings once

On the engine side i havent done very much more than you but still:
As i mentioned before :
replaced oilfilter housing gaskets
replaced valvecover and its gasket(new pcv came with the valvecover as its built into the cover)
replaced ignition coils
in addition to that:
intake valves cleaned from carbon deposits
replaced aux belt and tensioner
replaced hydraulic chain tensioner
replaced front and rear main seal
replaced water pump and thermostat
replaced oil pan gasket
replaced alternator
replaced boost solenoids (preventative)
replaced all vacuum lines (preventative)

Now other things like electrical, trim etc repairs:

trunk lid harness plug connection had to be cleaned as it had some moisture allowing for voltage to jump from one circuit to other and that tiny voltage kept a small part of my third brakelight to be on all the time.
replaced rear taillights due to moisture getting inside
replaced roof salmon relays
replaced driver seat base heating element
replaced door tweeter grilles both sides... A repair shop happened to bend them
retrimmed steering wheel
fixed hall sensor wires in rear roof shell
fitted new xenon bulbs and angeleyes bulbs.
Replaced drivers seat ivory white nappa leather with the leather from a donor seat that was in great condition...
replaced both mirror adjustment motors
replaced one dimming mirror glass
fitted a new original windshield
replaced rear numberplate lights
repaired trunklid softclose wiring both left and right...
replaced one of the rear parking sensors..

+ all the cosmetic stuff... refurbishing wheels, paint, polishing, waxing, ceramic coating, protective film on headlights, interior care.

Car is now at 127k km-s, thats about 79k miles.
When i got the car in 2016 it had 82k km-s on it thats near 51k miles.