[johnyisthedevil]

what he's saying is that if you take a system that is designed with the cans on it for the most power it is tuned with specific length, diameters and volume. so what you said is not true. ie if you take said system that has a length tuned to maximize scavenging and anti-reversion, and then remove some of that "tuned" capacity you have effectively negated the benefits of the system design and will lose power. it might sound faster, but most of the time it isn't.

a side note: straight through mufflers; like most non factory bike mufflers, flow just as much as a piece of straight pipe. and depending on the design of the louvers can actually flow more by creating micro turbulence along the wall which helps to increase velocity. which in turn helps with scavenging and creates more power. so the can vs no can argument is really a moot point, and you should be thinking more about things like optimum length and diameter