The Garage Star rear differential mount bushings will be made out of Delrin. The Garage Star Delrin bushing will replace the stock rubber differential mounts. This will limit drive train movement and improve shifting. The differential bushing will fit 1990-1997 and 1999-2005 Mazda Miata’s.

http://garagestar.com/shop/rear_diff_bushings.html

Price will be $55 per set (two) shipped within the USA and $72 shipped anywhere in the world

Hey Ken, I'll be hitting you up on these and a latchless cooling panel soon my friend