I actually just heard from Romi himself with regard to how he modified these mufflers.
I thought that the black, slash-cut outlet tips looked larger than stock in the video, but at first, I attributed this to camera angle.
Romi confirmed that he surgically gutted the mufflers and installed a new baffle system...probably something like a small glass-pack or cherry bomb muffler.
So, the "tinkering" that the owner refered to in his YouTube posting, was something of an understatement...especially when Romi wants $500 to do the modifications.
It would be much more cost effective to order a set of Cobra Classic Slip-Ons
I'm now torn between ordering the Cobras or using a 1.25" dia. bi-metal hole saw with extension to drill out the three inner baffle plates on each muffler.