Freja,
Borzilla comes with its stock performance baffle or whatever name they call it or you can get it with the Big Bore Baffle.
The other fat cat series had the stock baffle, then a bigbore baffle, and now also offer a quiet baffle
You will find the Borzilla has a larger collector and larger stepped pipe than the standard 2 into1 called the Fat Cat and the pipe
503-32B 07 FLH/FLT Boarzilla 2:1 w/1-7/8" Primaries 857 f/s W/O2 Bungs
Available with Big Bore Baffle
503-32G 07 FLH/FLT Boarzilla Ghost Pipe 254 f/s Left side only
502-32B 07 FLH/FLT Fatcat 2:1 w/1-3/4" Primaries 725 f/s W/O2 Bungs
Available with Quiet, Standard, Bigboar Baffle
502-32G 07 FLH/FLT Fatcat Ghost Pipe 254 f/s Left side only
506-32B 95~06 FLH/FLT 2:1 Fat Cat 725 f/s w/O2 bung
506-32G 95~06 FLH/FLT Ghost Pipe
-harry