Getting these to breath is fairly simple. In my case, The first step is to correct the OE Honda exhaust flange welds. For some reason, Honda welds up the pipe to the flanges unbelievably sloppy, so that the pipe is restricted 20% or more of its diameter. They do not bother to grind it, just bolt 'er on. Take a look:
That is not carbon buildup, it is the weld!
A good chunk of time with the Dremel and you can begin to see the difference on the left side of the flange. This is still not finished, but it was so tedious I forgot to take another photo:
For the silencer, the stock one is not that heavy and worth keeping. There are inserts available on EBay that make it flow well, for very little $$$. But I wanted the looks factor of an FMF Q4:
Workmanship is great and the bike sounds good and is not loud.