The official answer.
Here is what the state statutes say:
"347.39 Mufflers. (1) No person shall operate on a highway
any motor vehicle subject to registration unless such motor
vehicle is equipped with an adequate muffler in constant operation
and properly maintained to prevent any excessive or unusual noise
or annoying smoke.
(3) In this section, “muffler” means a device consisting of a
series of chambers of baffle plates or other mechanical design for
receiving exhaust gases from an internal combustion engine and
which is effective in reducing noise."
Many people with the tuners cranked up to put out a little black smoke could also get a ticket if the officer wanted to. Most officers (state patrol doesn't could here as I think they were all born a-holes
) really won't look at you twice if you are behaving, but how many of us can do that!
It is that nuckle head that goes out of there way to make "noise" or show off that is going to get in trouble.