Being that it's an I-5, you are never going to get that rumble of a V8.
If you were to take a V6 and slap a flowmaster on it and start revving it like that, it's not going to sound much better. Also you need to take into account that this isn't true sound + the fact he is just sitting there revving it. Normal driving will sound a hell of a lot different than this in person. I have personally heard the Flowmaster 40 and 50, Magnaflow, and Gibson. So far the Mag and Flows sound the best IMO. The 40s and 50s have a decent rumble at idle.
But if you smash the gas, it's going to go higher and higher in pitch.