Emir, great to see you moving forward on your project.

I expect you already know this, but at the risk of being redundant, I’ll post anyways. Just thickening the skins in the motor bay area won’t restore the torsional stiffness of the boom. When the hole is cut for the doors the boom goes from a closed tube shape to an open “C” shape. This dramatically reduces the torsional stiffness and strength of that area. You can demonstrate it to yourself with a cardboard tube..

The factories get around this by adding a pair of vertical walls in the engine bay to form two closed “D” shaped tubes, essentially restoring the lost stiffness.

Good luck with your project. I’m looking forward to hearing how it works out.

Best regards,
Craig