Given the size of your engine, you will have no need and receive no benefit from the 3" kit. The 2 1/2 kit is more than enough, there are some sound clips at the Magna Flow web site. This is such a subjective thing, what sounds just right to some is far too loud and dronnes to others.
That being said, I like my Magna flow, not quiet nor too loud, no drones, but when I put my foot into it, the sound is just what I want.
I too have the 2.5" kit, and i found it to drone like crazy as a complete kit. But as soon as i took off the tailpipes, no more drone.? I like how it sounds.