Hello my new friends^^

I'm currently having an 4.8is out of late 2005 that has driven 200.000km. When i bought it the seller told me the valve stem seals were just replaced, no bills or whatever though. Did a lot of normal maintenance and after i replaced the crankcase ventilation system the car started misfiring on cil 6 and 7 and a few random cilinders. Did a remap at a BMW dealer and after 30 mins the cel came on, read it, map sensor failure. The map sensor turned out to be unplugged from the beginning.

What I've tried:

-new plugs
-new coils
-swapped over injectors (still mainly cil 6 and 7)
-compression test (all was 10.5 bar)
-new intake manifold gasket
-new map sensor
-new maf sensor
-new lambda probes in front of cat
-new fuel filter

The car runs very smooth with the MAF unplugged, for 1000km's now, with the every sensor plugged in it runs better and faster in the beginning but starts misfiring on 6 and 7 but also random cilinders after about 30km. Inpa shows this also in roughness, very smooth but when misfiring very rough on some cilinders. There was some oil laying on all of the intake valves when i replaced the intake manifold. It is leaking oil at the alternator bracket gasket and the vacuum pump, could this cause so much oil to be sucked in and cause these problems? valve covers don't seem to leak a drip, also almost no smoke from the exhaust under any circumstance. So what do u think? bad valve stem seals, the two named gaskets or maybe another issue ?