Vastly different registration requirements here plus our historic is 30 years. I do a lot of longer distance so livability is a premium. Luckily we don't have regular inspections so you would need to be defected and have the car checked to identify any changes in emissions, but other states are different.

I'm past the valves, flaps and speaker enhanced exhausts on new cars and really like the natural product where you can drive next to a patrol car and not raise any attention and yet get some roar when it matters.

You're in a good place with your upgrade when it's items like the exhaust that are your focus.