Some quick updates:

I removed MAF plug yesterday and started the car while it was completely cold (had been standing over 24 hours) and it was -4C outside. The car fired up really nicely, no sign of any rough running problems. Only thing was that I could smell that the car was running rich. After a minute or so I turned the car off, plugged MAF back in and fired it up again. Engine run fine.

Today car had been stationery for 12 hours in -4C cold and it started perfectly. Before starting I made a throttle adaptation (holding gas pedal for some seconds with ignition on etc) if that would have any effect, I doubt it. Again I have the feeling that today it started with 6mm valve lift because I could here the car going to closed loop after a minute or two (a small rev fluctation happens then). The engine ran fine during the cold morning, what a feeling. One possibilty is that the car hadn't cooled down with 12 hours. There was a thin layer of snow on the car that might act as a thermal isolation.