Unfortunately I can't go into details about specific models but we use both OEM and in-house made drivers. I am assuming you mean the woofer cone/diaphragm material? Polypropylene and pressed paper are the most common. You can find all sorts of exotic materials in the world but often the reality is that you end up paying 10x and having only 5-10 % performance increase, if even that. Not a very good deal.
Don't worry, I said the exactly the same thing in another thread: the price increase and nasty breakups aren't worth the effort when doped paper or PP do it as well.
Have you already checked our operating manuals for each model? There you can find all the available specs for our amplifiers. I can assure you they are as advanced as you can find available from any well known manufacturer you listed.
Oh, there's indeed THD in the specs. Looking at the 8030C, 0.05% THD really isn't much (unless "nominal output" means maximum), but I suppose speaker distorsion is still greater.
THD+N would probably be a better metrics, though.
Mechanical fitting/integration is one of the most important things for us because our amps are fully integrated into the mechanics/enclosure of each monitor
Should we understand that the whole enclosure is used as a heatsink by both the amp and power supply? That'd be very cool and seems logical when you can cast your box to the exact shape you want.