"The total number of throttle plates can be no more than the number of engine cylinders or rotors."

I don't understand this idea, a rotary only can only have 2 throttles (or 2 injectors for that matter) A rotary is treated different to a traditional combustion engine.

You are multiplying the FIA capacity by 1.8. Normally the housing is the block and the end plates are treated as the head. Not that I agree with this but it's just how it is. It comes with a 4 barrel manifold with 4 runners and a 4 barrel carby standard, going to 4 internal ports (there is even a 6 port block). No different to a 4 cylinder. You are allowing other engines the ability to change their heads. (twin cam, valve sizes and angles) Porting is another item, you should be allowing peripheral ports as this is a very common modification is this era. 12a housings are very hard to find it is very common to machine a 13b housings to the same width as a 12a. There is no power benefit to this only cost. You can't do much with a rotary and modern technology compared with 40 years of piston engine technology.

It is an unusual scenario that the Group NC RX2's seemingly have no ability to run a aftermarket 4-barrel carb and intake manifold even though that is what the cars were equiped with as standard. This issue pertains to all 12A RX3, 12A and 13B RX4, 13B RX5 and 12A RX7 that could potentially run in a proposed ND format. However I can appreciate the IDA Weber carb offers sufficient performance and is ubiquitous with the era. As for the 1984 EFI 13B and EFI 12A turbo RX7's how will this be managed? Six or four intake ports, four intake runners, three single-blade throttle bodies, two injectors. Can this be accommodated within the scope of aftermarket intake manifolds and induction?

the RX2 is already approved for Nc group and the 12A engine is detailed in the specification documents for this car. there is an extensive discussion in Appendix A of the specs
1-model experts are needed to work out how best to translate that to 13B engine used in RX4, RX5 and RX7
conceptually, i think the rotary should get similar levels of freedom to piston engines, eg porting, carbies etc, but the devil will be in details. what we dont want is RX7's (for example) dominating every event, like they did for a while in 3J
mazda-rx2---nc.pdf