First off. HEY, MAN! Secondly. Sick project!
Few questions:
Did you close up those vents on the baffle recessions above and below the drivers? Didn't see anything on this and that would definitely kill bass.
Did your T40 have bass distortion before the mod? I'm thinking it might be the new PVC pipe magnet clamp thingies being slightly off alignment, or something. When you start talking about using the driver housings as physical 'springs' to clamp the magnets I sort of cringe. Perhaps I'm reading you wrong, though. Do you have any other photos of the driver assembly? Not quite sure I understand what is holding everything (diaphragm and magnets) together, or how.
Ever thought of a different (non-porous) material to angle the pads with?
If you wanted to try a re-mod of sorts (or just listen to what I had in mind to perhaps get the juices flowing in yo' brain), you could get some Lucite, cut 4 discs to maybe 5mm larger than the magnets (with holes in the center just big enough to not obstruct any magnet perf's), lay the magnets onto the discs, shape some epoxy putty around the perimeters of all the magnets making sure everything's nice and centered, after maybe 20 minutes pop the magnets out so they aren't cemented in place and you can clean them easily with isopropyl, then once the epoxy putty has fully cured you can pop the magnets back in but so they'll attract instead of repel when you put the halves together (perhaps put a piece of very thin foam between the magnets to protect them from scraping and any other danger), then finally drill some holes just outside the magnets so you can clamp everything nice and tight with some nuts/bolts/washers when everything's ready for assembly. Your drivers would still be recessed by the thickness of the baffle plus the thickness of the Lucite, of course, but maybe it could fix the distortion issue? Also, you'd have to center the diaphragms between the magnets by eye before clamping it all unless you modified the to-do list I just described with a couple more steps. Idk, just the ramblings of a fellow modder.
And to Ludoo's inquiry, imo the Phiaton offers an angled recession that doesn't increase the ear chamber volume quite as much as some angled pads would, and it also doesn't require heavy modification to the stock T40 baffles. Some DIY'ed angled pads
could mimic the Phiaton platform, but they'd be difficult to make look and sound right, imo. They'd probably look something like maverickronin's SR-007 clones (v2?) that he made for his T50RP's. Ime, pad rolling has probably one of
the largest effects on overall sound out of any modification. Tricky beasts. '
-edit-
Yiiiikes. Just saw the time stamps on all the previous posts. Muh bad.