Ron - It's a rather bizarre argument between Porsche and Audi regarding the "RS" badge Basically Porsche has reserved/registered the rights for the "RS" and "RSR" badge.
Audi is allowed to use model designations such as "RS4" or "RS6", but Porsche claimed they are not entitled to use it with a blank space between the characters and the number such as "RS 6", hence the lawyers started a bizarre debate about which size of the blank space would be legally acceptable

Anyway, they now settled the argument: "RS 6" with a blank is accepted by Porsche