I'm running PS2 at the front and PSS at the rear. Plan to switch the PSS all the way around eventually. Having said that, I only drive the M3 on the streets, not sure I'd do that at a track event.
Current: 2008 BMW M3 Sparkling Graphite/Bamboo Beige/6MT. 1999 BMW M3 Techno Violet/Dove/5MT