endcaps

Hi, i have the UFO 4-2 exhaust, the earlier style before they switched to megaphone style.... mine has the 2.5" opening endcaps, too loud for me. i see that they now sell the SBD end caps on their website, does anyone know if they will fit my mufflers? i have asked UFO 3 or 4 times over the last...

Has anyone changed the endcaps from the more standard closed endcaps to one of the optional open endcap designs? Does it change sound? I'd imagine its louder, but more importantly, does it increase/decrease the lower, boomy tones?

I know some out there are using trapps with several discs, and some open endcaps. I've also been told folks have run both at once. If the endcap is open wouldn't that defeat the need for discs? Is this done for sound? I'm getting a set of trapps when my tax return comes in and I just...