OK so I know I'm a latecomer here but let me say this, you gotta just look for other V6's with modified exhaust and have them rev it up for you, the sound clips all will sound different depending on the audio equipment that they are replayed over, and you can't make a good decision based on that, as far as my opinion on the best sounding on a V6, I did what I suggested and actually would pull up next to other V6's that had exhaust different from stock and asked them to rev it up, so they would rev them up and I would tell them it sounds great { I believe if you can't say something nice don't say anything, and everyone is proud of there car, and its nice to hear a compliment every now and then} and ask what brand it was and then either cross it off the list or do more research, that is until I heard the MAC, I was sold and love them, however, they drone badly inside the car so if you think thats not acceptable I would tell you not to get them, I love them and just ignore the droning and turn the radio up just a little louder LOL, I've had them now for 5 or 6 years, and have no intention on changing.
I hope this helps, I know the pic there is of my II but I also have an 05 sonic blue V6 that I love, her name is actually Big Blue.