Sorry to tell you that on the basis of pure law that technically anything other than factory manifolds is illegal, even in Florida. Exhaust manifolds are directly related to the the emissions control function of the engine and it's a violation of Federal law to remove/modify them. Same goes for the mid-pipe. Once you are past the catalytic convertor, things get more free to being changed.
That fact said, many people change them and nobody is the wiser as the Federal government has no enforcement capabilities and each State may or may not check them at their discretion. Many States say don't change them, but also don't check them. NY, for example, says don't change that stuff, but once a car is 25 years old all they inspect or is safety. They no longer check for emissions compliance.But for those first 25 years, if it isn't there and functioning you fail the inspection and can't drive till it's corrected.
I'd bet Florida says don't change it, but they don't inspect (last I knew) and have no method of checking nor desire to check at this point.
Not too long ago the Feds cracked down HARD on a bunch of companies and "off-road" mid pipes are drying up quickly.Not sure why this didn't get more press. Maybe COVID-19 bumped it off everyone radar.
https://www.hemmings.com/stories/2020/01/14/epa-launches-crackdown-on-emissions-defeat-device-makers
The long term ramifications are still to be seen, but expect non-compliant stuff to start drying up. The EPA has decided to hold the manufacturers responsible for supplying product that end users put on their cars to defeat the emissions control functions.
From the article....
"EPA will vigorously pursue and prosecute companies who attempt to circumvent emission controls that are required to reduce air pollution," Susan Bodine, the EPA's assistant administrator for enforcement and compliance assurance,
said in a statement. "This case illustrates why stopping the manufacture, sale, and installation of aftermarket defeat devices is an EPA National Compliance Initiative."
and
"According to the EPA, its
National Compliance Initiative, which "will focus on stopping the manufacture, sale, and installation of defeat devices on vehicles and engines used on public roads as well as on nonroad vehicles and engines," is slated to run from 2020 through 2023, though the August and September enforcement actions listed above were considered part of the initiative."
It's clear that the during the next phases the EPA will almost certainly go after the sellers and installers of these products. After that, they will be down to the owners. Us. Enforcement and change are coming. And it started before I was born.
https://www.epa.gov/transportation-...line-major-accomplishments-transportation-air