Thing is with aftermarket cans is that they all essentially sound the same - its just that some are louder than others.
Shorter ones will have slightly more of a rasp - longer ones will have a slightly deeper note.
I have a Kerker carbon can on my bike & as a race can it was too loud for my liking as a straight through jobbie, so I fitted a universal baffle kit to it (£10 on ebay) & now it sounds gorgeous, but not too loud.
I think you just need to select the can you like the look of/fits your budget & go with that - as I said, the sound will be similar whatever you fit. Its just the noise level thats different