How many pars should you get in a round

Depends a fair bit on what you mean by 'aim for' too. If you're talking about a post-hoc benchmark to grade how you played then an aim is fine, but when you stand on the first tee you don't want to be thinking "right, today I must make 8 pars". You don't really even want to think "I want to par this hole", you just want to hit the best shot you can. Do that all day, hit every shot the best you can, and you'll probably find that the pars take care of themselves.