The stock exhaust system on my Futura sounded terrible, like a sewing machine, as many others have said. I already have an H-pipe installed but it had this tinny, raspy sounding exhaust note that was anemic.
I found a pair of Dominator cans to replace the stock mono-muffler and the improvement is huge. Not as deep as I’d like but close enough - sounds like a real v-twin sport machine now. Louder too, but not obnoxiously so. I still need to take it on a good ride but so far I’m happy.