Gotta agree. Get some tailpipes on there and see how much it quiets it down. If not enough add the crossover. Then finally the mufflers. You could probably get some coin back from selling the FlowBastards.
Btw, my Demon dumps the FlowBastards like yours does. I find it way too loud too. Maybe we're just getting old! I want to put tailpipes on but with my springs moved in, it'll be a job putting on 3" pipes out back.