Sorry to hear of the broken mid drivers.I currently use Martin W3 (2 boxes per side splayed horizontally), they're running off a Powersoft M50Q with the recommended Martin corossovers/delay/EQ
This brings me to my questions, my current shortlist for replacements are 1 pair of SynTripP or 1 pair of 2x10 Paraflex, would either be able to provide similar (or greater) SPL and response than I'm used to?
Not familiar with the 2x10 Paraflex, but as a tapped horn design, it may have as much as 6dB low frequency output gain over the bass reflex SynTripP. You could compare different designs using the Hornresp simulation program.
http://www.hornresp.net/.
The SynTripP has only about 125dB output potential, less than a single Martin W3, and won't go as low.
The SynTripP may sound better due to it's virtual single point source, but a pair of Martin W3 would be far louder- comparing under 100 square inches of cone area (2x10") to around 264 square inches (2x15") is not a close race.
The Faital pro HF146r has a 65 mm (2.56 in) diaphragm, so would be pushed near the ragged edge keeping up with 2x10" on a 90x40 conical horn crossed in the 800Hz range. Used with mid drivers, crossed over higher, it should be adequate.
From what I can tell, the Martin W3 uses a B&C DE16 HF driver, with a 44 mm (1.7 in) diaphragm, which won't have the output potential of a decent 3" or 2.56" driver- if boosting the VHF doesn't provide enough "sparkle", they may be at their limit.
Art