I got new Mazda competition motor mounts from miataroadster.net while oredering manifold studs.  I hope this will somewhat make the six-speed shift better without too much NVH. Also  the turbo/DP is less likely to hit the subframe/ steering rack.  3" is a tight fit.

Installation is pretty straight forward.  Car on wheel stands.  Jack up the motor a couple of inches with the OEM carjack under the oilpan.  Use a pry bar to move the engine and fiddle out the mounts and brackets.

There are some confusion about the Miata motor mounts.  There is at leaset 3 different mounts:
- Miata/MX-5 motor mounts
- Mazda speed mounts as found on the MSM.  These are supposed to be stiffer.
- Mazda competition motor mounts.  Stiffest.  Meant for Spec Miata etc.

The ones to get is the competition mounts.  Not the MazdaSpeed mounts, as they are probably the same as the regular mounts but with a higher price tag ( just like the MSM exhaust manifold gasket..) 

Comparison shot.  MSM mount to the right: