power. to. weight. ratio.
That's why some forced induction cars are fine and permitted (and also evidence that the blanket rule was stupid).
But the reality is most P platers who want a turbo car are going for the "fully sik turboz". I know this because I was one of them but hey, if I can wait it out, I don't think it's that hard for others either.
ps. I don't get the point of ur post... it didn't really add any value considering I was just replying to an obvious question.