Think he means to define a single operator to narrow it down.
505pp for life....550 would be my second.
505 in my experience since having game at launch day, gives more clean races and allows more variables of cars to race.
Most 550PP races I get into consists of people who can't handle the easiest of cars (GTR's etc) at a range of ~500HP.
505 gives the player ~400hp and most can manage to keep their cars on the tracks. "More power" fanboy's usually can't handle their cars. Go into a 550 - 600PP race and GENERALLY speaking, its a mess.
505 centralizes on accuracy, consistent race line, and car control.