So, finally a little update...
After some time driving in the Alps with a black MX5 I borrowed and hitting a snowstorm just outside Munich...
...my brother and I reached D-Fence's garage (only crappy phone pics
)...
...to pick up public's car.
On the way to Frankfurt the car ran quite allright if not really on full strength (the previous owner suggested changing the spark plugs) but the oil pressure went all the way to max at everything above 1500 rpms or so. After having it investigated by the finalgear hive mind we carried on, taking it easy. I checked for parts the next day and had the 4 year old oil changed (which didn't make any difference pressure wise).
The following day I had a look at the engine at a friend's little garage. The engine was completely covered in fresh oil, which was at least in parts due to an almost solid camcover gasket. I changed that and also the sparkplugs which were pretty worn and one rather corroded.
It revs better and drives stronger now with the fresh spark plugs, we want to have the pressure checked at a garage to make sure it's not a problem on the drive towards Finland in about two weeks. I'll have to see if I can squeeze it in tomorrow as loose_unit is picking the car up on Saturday. There's another gasket for the camshaft position sensor to be changed as well.
I can't update the infamous fart list for now as I left it in the car and don't have it with me, but I'll be at the place it's stored tomorrow and will update then