Stock exhaust and valve train are nice, not too loud at highway cruise....
You might find that at the higher RPMs, you hear a lot more cam noise than you'd expect from a Detroit machine.
No, it doesn't quite sound like a sewing machine like a Porsche, but my race buddies first comment on hearing me drive up was, "Wow! It's got a cam in it! We heard you from way down the street."
Having said that, what you will also find is that for long cruises at highway speeds, the exhaust is remarkably quiet. In point of fact, inside the car with the top up in the manual transmission car, you hear more drive line noise at freeway cruise than either of the other three sources, intake, valve train (cam), or exhaust.
Yet, with the top down, pop the throttle and the exhaust will bark quite nicely.
Then, too with the manual, it's fairly easy to chirp the tires from first to second with a good firm shift....
It's a nice balance. Drive it for a while stock before you put on an aftermarket exhaust.