There probably aren’t many of us left who remember the Mazda Wankel engine: “Piston engine goes pop-pop-pop-pop pop but the Mazda goes Prrrrrrrrr.” It had reliability and fuel economy issues but was finally killed because it couldn’t meet increasingly stringent emission standards. This one seems to have issues, as well. It’s complicated and likely heavy due to all the extra parts. Roots blowers are inherently heavy and inefficient.
I had an RX3 Wagon...ran like a scalded dog. at times felt like it might lift off the road...not that i was speeding or anything...