JD Z655 muffler

[dinoedwards]

25hp Kohler CH25S 68624 muffler replacement.
24 786 12-S vs 24 786 11-S ???
Is it difference in flange size or what? Kohler site has both but can't tell difference except 12-S is $50 more?
Mine flanges are 2" hole to hole overall 2 5/8"
I heard some newer ones will not fit older units, this is an older JD655M zero turn.
Amazon has both 12-S $140. 11-S $169 Amazon, Ebay $99 w/o heat shield or bracket.
Ebay has 12-S $169 complete with shield and bracket.

 

[dinoedwards]

I think it may be just that the S-12 discharges from left and S-11 from right.