To add to the confusion, Michelin also has the new Pilot Sport 4. That tire doesn't hold the same ultimate performance focus as the PS4S and is exclusively a European-market tire, outside of a handful of OEM applications. That's why there is an 'S' in 'PS4S,' signifying a level of performance beyond the Pilot Sport 4, similar to Porsche's badging scheme for the 911 Carrera S versus the standard 911 Carrera.
"We had some pretty demanding requests from product marketing (for the PS4S)," said Carl Driver, senior product development engineer at Michelin. "They wanted better dry/wet braking, lap times and rolling resistance. They also wanted to maintain wear the 30,000-mile warranty. Take everything we had with the PSS and expand it that's the PS4S."
