Thank you for your reply.

I live in Norway and was tipped by the guys at Dynabel about these Scanspeak drivers. They gave me the link to Zaph audio. After a bit of Google I stumbled upon this forum and the TRT kit from Selah.
Can you give me more information about the kit? The website doesn't say much. Got any .pdf or pictures to share?
If I were to build this speaker, I'd probably import the drivers and crossover from Selah, but build the cabinet locally. If that kit is the one that you used to build yours. It looks stunning, and the low tuning is what I'm looking for.