Hi Benjamin,
The high VRAM usage is due to the fact that, even if it is not an "easy fps aircraft", Aeroplane Heaven developed the model only for v4.
The v5 version is just the v4 version with a installation patch to make it work with the new version of the sim. In fact, the v5 version still has a lot of visual bugs, such as the green windshield other lights problems and high VRAM usage.
Me and other users have already reported these problems, and the @FeelThere team is aware of these issues, hopefully working with Aeroplane Heaven to fix them. I think they have to work with the model (MDL) in order to make it work with the new shaders and light system of v5, optimizing it to consume less VRAM.
I think it is not a big job to do so let's hope this will not take too much time.
Regards,
Riccardo