Paul,
I haven't mentioned this before, but I recently purchased a spare 20B with
plans to convert it to a P-port.  I'm in no big hurry to start an engine
swap project any time soon, but it is definitely in the works.   I'll need
to find three junk turbo housings to get the exhaust inserts from.  Stay
tuned...

Mark

Mazdatrix has a few junk housings for about $30 each.
Also Dave Atkins has dozens. Maybe Brian Trubee knows
what happened to Dennis Hayes Rotary Engineering parts supply.