How to change rev limiter and how to change settings on levels already set.

go to "modify" tune

You can't adjust the rev limiter, but you can adjust the speed limiter.

Is it good to have the speed limiter all the way to 160MPH or is it good at about 120MPH.

Set mine to max. Never going to have it that fast but why not.

I have mine set 120 mph. I think that is fast enough. I'm not sure how much faster it would go anyhow. And not to mention I have sat my but in jail for massively exceeding the speed limit.