I'm surprised no one has done it yet. I wonder if anyone has swapped a different motor into the RX-8 yet.
And guys, I wouldn't hold my breath for a MS5. lol. I'm sure someone will do the swap someday soon.
Kev
Yeah, basically many Japanese performance motors have been installed into the RX-8 chassis. Silvia/180sx's, MK-IV Supra's, RX-7's, Cosmo's, LS1's have all been installed into the RX-8. All of them were relatively easy swaps. Physically, they only require modifications to the front crossmember to adapt different motor mount positions, as well as a custom driveshaft.
The reason nobody has installed the MS3 2.3L into the RX-8 is because of its transverse layout. Once the Miata, with the longitudinal layout, releases with the 2.3L turbo, people may swap the motor into the RX-8...