Hello Troels,
Finally I can share my build of a set of Faital 3W Classic-15. Well, isn’t DIY about setting your own fingerprint on things? I got quite inspired by a friends set of JBL 4367 in the design phase. I took the liberty to widen the enclosures by 15 %, to obtain the right proportions. I also needed slightly curved front panels and grill. The curved panels I laminated from 3 x 10 mm Black HDF!!! Even if had nice customized 3D printed ports made, I choose to position them on the rear. Partlye due to avoid mid frequency radiation, partly to avoid difficult construction. The list of additional gimicks include:
38 mm sandwich panel enclosure, including damping glue and bitumen pads
41/66 mm front panel
Triangular MT cabinet, to reduce reflections through the cone
Internal Helmholz absorber, to avoid standing waves
Double flared ”FlowPorts” as by B&W
Separate and easily accesible enclosure for the cross over
Countersunk and protected Neutrik SpeakOn connectors
Additional SpeakOn connectors for easy connection of optional ”ambience” speaker units
Wheels and and grip slot for manouverability – is really a necessity. I estimate weight to be around 80 kg each
Except for Wheels and grip slot, it really is only gimicks and fun
 
As I have not heard your original design, I shall not be able to judge the audible impact of the changed width. Anyway, measuring with REW/MiniDSP Umik, doesn’t reveal any problems over  say 250 Hz. Now we are at it, these speakers seem to have the least ”need” of any bass correction, of the ones tried in my room – including my DTQWT MkII. Even if the 18Sound drivers are routed into the curved front panel, offset from the tweeter is exactly in accordance with your design. As you can imagine, I did not go for ”ease of construction” with this build. But most of it was quite striaght forward and just a bit more work. What knocked me out during the process was the paint work. I ran in to several bad cases of components that didn’t work together – even if I bought all products by a professional and only in accordance with his advice. Luckily he was was very large and helpful, limiting the additional cost to countless evenings of sanding and painting. My advice to other DIY’ers: Pro looking paintjob requires a pro painter!
Performance? Even with ”Level 2” and the SBAcoustics fabric tweeter, this is undoubtedly extreme high fidelity. Regardless of the genre! What has really given me a kick is Danish male singers: Ivan Pedersen, Johnny Madsen, Peter A. G., Peter Belli… add who ever you like. The stunning dynamics of these speaker really lifts some dull studio recordings to live events in you Living room. Bass is extremely well articulated and easy to follow. And it goes deeeeeep! I couldn’t have whished more from my investment and effort. Thanks a lot and feel free to share on your fabulous site.
Kind regards 
Lars