Wayne Parham Messages: 18856 Registered: January 2001
Illuminati (33rd Degree)
Both of those mods are fine. I usually flush-mount drivers, but not always. The crossover is good either way, because the fore-aft offsets are acoustically small.
As for MDF or plywood, either is fine as long as the plywood is Baltic Birch. You definitely don't want any voids or the debris in the voids will buzz. Baltic Birch is void-free.