In my O
You gotta be careful about a lot of this info

and
Stick to common sense
Everybody has their own idea of what is loud and whats not
A guy says his such and such muffler is quiet
but
He has only a bolt on or two
A different guy using the same muffler with h/c/i and offroad mid pipe
well
He says his e system is pretty loud
Here are a few things you can know are a known
No cats will make ANY muffler more loud
and
Cats will tame down ANY muffler
More power will mean more noise
I still run the stock catback
I had a mild oem based combo with self ported E7's and the like
When I went to my all aftermarket combo ......
I could not believe how much more noise the same e system made
Hey ... if you are gonna go with some cats ..........
You might wanna see how much the cats tame things down with your
current muffs before you buy different muffs
Grady