Good morning Troels.
Third design of yours I have built. 
Faital 10-340, only had about 20 hours of play but already bass is loosening up. Very happy indeed with the sound of these, I had my slight doubts using PA drivers but having built the previous two kits I was confident that they would sound good.
Only alteration to design is faceted front baffle just to take away the edge to it. Automotive paint finish dark grey with black baffles and 2K satin clearcoat finish. What my next project will be I don’t know yet, but will have a 15 inch Bass driver.
Kind regards
Ian