What number stailess and thickness did you recommend for the Renesis
exhaust?? Right now I am just looking for a 90% elbow to add on to the
regular  RX8 mamifold. Karibian

Depends on where it is. If right next to the engine
I would use .065. 10 inches down the pipe maybe .049.
321 SS if not 321 SS go up a thickness.

Paul Lamar