2008 Mazdaspeed 3, I have tried M1, Royal Purple, Amsoil ASL, GC and PP, all 5W/30, except the GC of course, and I feel that the car runs its best on the PP. This coming from a long time M1 user in my turbo cars and Castrol GTX in my old 440 and 426 HEMI mopars. I realize this is completely subjective but it is how I feel. I am planning another OCI with the PP but in the near future I may try the Redline once the powertrain warranty expires.