Yes. Because it's an enduro.

The tire rule experiment is allowing a very small number of teams to run in an "X" class one "Enduro" class lower than where their car would otherwise end up, if it's on gen-u-ine street tires. The RX8 I'm in would be an E2 car (by virtue of it's NASA PT category classing), but is running E3 on non-R rubber.

K