I had decided to order a pair when I noticed the following:
- the silencers are 4" in diameter and 32" long
- Tailgunner has 4" diameter silencers but max 28" (they offered to make a pair of 32" at no extra cost)
- the right hand side factory silencer is about 3.13" from inlet to the rear mount point (well 16", mount point is 18.5" from inlet). That's to clear the rear wheel shaft drive assembly.
So basically, the left hand side silencer is ok, but a 4" silencer can not fit on the right hand side because of the shaft drive.
Also, I believe they provide a straight inlet pipe although the F6B outlet is sideways. So it would require some bending or adding/replacing a tube.
I noticed that Two Brothers do provide bent inlet (different right and left), so it seems to be a direct fit.