I have the aps 3/2.5" tbe with single tip muffler, and I am running catless. My experience is quite different than Blair's.
While the exhaust does get uncharacteristically louder from about 2500-3200 rpm, it smoothens out nicely after that.
There is no drowning at highway speeds in my car. With the windows down at these speeds, it is not very not loud at all, but becomes more noticable with them up. Still it is not at all bothersome, and I am partial to quiet exhausts.
As Blair said, quality and fitment are awesome.