No they don't need to be stock - they just need to be legal.
I have a set of slip on Screamin Eagles Street Performance mufflers & I doubt they would pass any test. I don't think the words "50 state street legal" mean much to the EPA.
You only need to be dobbed in once to get a letter. Even if you have stock mufflers & some knob head rings the EPA & dobs you in then you still need to pass a noise test - guilty until proven innocent.
& yes, of course the EPA keeps a record.
Been there done that.
So I guess you are saying my SE2 s without baffles might be slightly over so far so good though and keeping my fingers crossed.
I asked the bloke who tested my bike why it's stamped 98db (ADR approved) on the swingarm when EPA states 94db. He said Harleys are allowed the extra 4db stock, but if you put aftermarket pipes on they have to be 94db. Rediculous!
Fuk - can you turn that the right way up. Been following this story with much interest. - - - but had to whip out and throw up when I got to the execute in court bit !!! You try reading this shit with ya head parallel to the keyboard on a belly full of rum ! Good luck - is interested in how it all pans out for ya.