Strangely enough, the issue had nothing to do with anti-aliasing, changing the texture quality was the key. After reinstalling both the drivers and the addon, and two hours of messing around with settings, I noticed that changing textures to MAX resolves the issue. I didn't notice it at first because it takes couple seconds before the changes are applied in the game. So, that's the solution, I guess. It seems that at some point I switched my settings from max to high for some reason and that caused the artefacts. Still no idea why changing texture quality decimates the resolution of the whole model, or so it seems
Anyways, thanks for help! This is a fantastic plane and I absolutely love flying her! Keep rockin, IXEG!