Good evening gentlemen,
thank you very much for your kind, encouraging words! You really help me very much with that.

Tonight I finished the interior including the engine. I won't detail it more, it won't be visible.

I changed the cable of the shot counter clock (is this the propper term?) and added the Machine guns and empty cartridge connections between gun and box. Here I actually would like to give two recommendations regarding the built:
1) I didn't regret having glued the engine in place and after this adding the wiring. It's no problem to detail the engine when it's glued in place.
2) Especially when using aftermarket guns I would highly recommend to align engine, MGs and empty cartridge before adding the upper decking.
If you cut the decking at the front (where it is split in reality anyway), you can bend both halves and add the decking in spite of fully mounted guns:

Thank you for your attention.
Best wishes
Borsos