Our engine mangement system has knock sensing so if lower octane gas in put in such as 89 or less (Porsche says 91 i think), then the motor will "retard: timing slightly so engine doesn't knock. Driving around town isnt a big deal, but at 10.9:1 compression, under load, or high RPM, the engine may feel a bit sluggish.
Put the good stuff, go with min octane rating 91 or better.
