While the tone/decibels will be the same between rigs, how the driver (and passengers) perceive it is highly variable. It won't bother some people at all but will drive others crazy. Since the Magnaflow system lacks a resonator and has a rather small muffler it would (from my exhaust saga) personally drone too much for me. Somewhat oddly, when my exhaust had drone issues, it really didn't bother my wife and kids at all, even though it bothered me.
If you have to ask "will it be too loud", then it probably will be too loud for
you 
. The best off-the-shelf drone-free option for a GX is a Dirty Deeds - not cheap but worth it. Otherwise, if you are drone sensitive there is a good chance you'll end up unhappy with a off-the-shelf exhaust and selling it, or hacking it up to add resonators (which I did). If you aren't drone-sensitive, $625 is a great deal on that exhaust.
FWIW now that I have mine dialed (with
three resonators - a Vibrant, quarter-wave, and a Helmholtz), it sounds awesome without being intrusive and adds to the driving experience.