A new thought for twins - Compound Turbos? Maybe?

[dudemaaan]

Compound charging is one of those things that looks like it wouldn't work right, but apparently with all the success in diesel engines, and now Supras and other cars it apparently works quite well. The easiest method is to use at least an internal wastegate on the first turbo (smaller one). And for a rotary you'll want to make sure the wastegate and housing can flow enough so as not to become a bottleneck.