Special Exhaust

[Underdog]

I recently bought a complete exhaust off ebay for an XS11 special. I was thinking about haveing them jet hot coated for my Midnight to replace the black chrome ones since I haven't been able to find anyone to redo them. Anyway, the mufflers on my bike have 4 holes around the center outlet whereas the ones I bought just have the one center hole. I saw another Midnight here locally that also only has the one outlet hole. My question is, does anyone know what the difference is, why the extra holes and if one setup sounds or runs better than the other?

[chevy45412001]

4 holes

my stock XJ has the four hole muffs. Maybe someone traded muffs at one time for the xj version?