Well, the impact driver could not be found on short notice, so i gave the brutal method a try (it felt more like a dozen tries :shock: ).
However, i opted for a few luxuries as i worked on my parking space, therefore no traffic to worry about, and i used an assistant to operate the starter, instead of pulling wires and giving an one man show. The 4 cyl base unit is not very convenient to bang the 3/4 breaker bar onto, actually it would crash on the starter solenoid, while the placement of the water pump didn't help either. I had to be creative with blocks of wood to end up with something that appeared to be safe. So, i was holding the socket to the bolt while the assistant operated the starter. After quite a few times, i thought that i should stop as it didn't seem to have any results. However, before giving up completely i put again the car in gear, fitted the extension to the bar, and pushed some more and... i felt it moving.
Yep, it was undone. So the trick worked, but i still think that the use of the air impact would be the prefered way to work.
Other than that i spent my day by fitting the drier (which necessitated fitting the expansion tank further back), planting and welding a captive nut to the base unit for the lower engine steady bracket, fitting the main compressor bracket / front plate, moving the nylon alternator adjusting strap, and starting on the condenser mountings.