I did it a few weeks back out of boredom. The only time when you're really going to have to rev the car hard (i.e over 4000RPM) is when you're close to the top, otherwise the car should have adequate power to get up.

Edit: That's also assuming that you keep your car in a good condition mechanical wise, e.g no extended engine oil usage, performed throttle body cleaning, and et cetera.

Edit2: Sorry, I thought you were talking about Genting Highlands with a Persona. For Cameron Highland, my last memory of the journey up there is that it's not that bad. The route's gradient is about the same as Genting, or not as bad as far as I remember.

P/S: I used to go up there yearly or so as my relatives live there, but in a Nissan Serena C24, with about 5 people on average and luggage.

Cameron highland roads are nowhere as steep as Genting's, quite pleasant to drive actually.

How many people need to carry to cameron highland ??

4 adults also no problem.