I don't see the need for a 'bridged' intake port on the RX8 engine.  The RX8 also uses a 2mm apex seal; I think we can grind the RX8 rotor apex seal groove to the same depth as the older rotors then use Tracy's or Hurley's 2mm spex seals in a peripheral ported Renesis.  You should be also be able to use the lighter 8.7 lb RX8 rotors in the  older engines if you get the rotating assembly balanced.  Wish I had a RX8 rotor so I could measure the critical dimensions (but not bad enough to buy one!(grin)).

Ken Powell
Bryant, Arkansas
501-847-4721