well i bought mine by itself, but its not electronic (there is a cable with a lever inside the cabin) and it cost me nearly $200 - but then that was when the only other option was the apex'i ones for $400.. mine is 3" though.
if i were you, i'd buy the pox muffler, then rip off the valve (provided its big enough for what you need) and then re-sell the pox muffler to some kid. cant go wrong.. maybe.