I got mail from 949Racing today announcing the new new M-tuned coolant reroute for all Miatas.

Compared to other reroutes I have seen this one has the thermostat in its own housing on the return hose rather than integrating the thermostat from the outlet on the head.
This should make the installation easier and hopefully fix the issue with the water returned from the heater making skewed temp readings when using the JR-spacer etc.
For the remote thermostat work there needs to be a certain amount of water bypassing the thermostat.  Hopefully the thermostat housing has this integrated instead of having to drill holes in the thermostat.

For $295 its very expensive.  The only part of any real value is the reroute adapter and block off plate.  The rest can be bought at Biltema/Torshov/Napa for $50.