https://www.youtube.com/watch?v=vqSuTAyJHF4
I can't say anything about 12 or 18 in resonators. But outside of the car, this is what it sounds like with CF non-resonated on stock cats and G3s.
Sunday the guys here on the forum got together. I can't remember who said it, but someone said that the volume outside the car is the same. If you want to use your bluetooth, you need to get resonated. The more important phone calls are, the longer that resonator needs to be.
My radio is fine at all speeds. I have the bose package with the crappy sub. I stream music from my phone through my car and use an app called "bass booster". Makes the sub hit decently and drowns out any exhaust noise....but honestly I just listen to my car most of the time.
Don't know if you're military, but Tony will give you a mil discount if you ask.