first of there was a proposed house bill no. 3574 to ban the sale or installation of an exhaust which has been modified to increase the noise. I don't know where this "you can't use anything other than factory stuff came from because that is bull. I have a copy of the house bill straight from the mass gov. website and it doesn't say that. if it isn't noisy it's fine, so aftermarket will work, and it's still grey area.
according to what I have found the bill(which is not law) if it was to pass was to be inserted in section 7 line 176 of chapter 90 mass general laws. I have printed out that section and it has not been inserted, all it syays is thsi "every motor vehicle so operated shall be provided with a muffler or other suitable device to prevent unnecessry noise". however, the same law under chapter 90, section 16"offensive or illegal opertaion of motor vehicles" still basically reads you can't run muffler cut outs, remove baffles and screens and other internal parts and part 2 reads.. or operate a motor vehicle with an exhaust system which has been modified in a manner which will amplify or increase the noise emitted.
now what is modified, if it still has cats, no baffles cut and a 50 state C.A.R.B certified system that isn't modified to me. that is the fight. I'm keeping a copy of the chapter 90 section 7 &16 and propossed bill in my glove box.
I want a trooper to show me where it says it has to have a stock system, what is modified and what is amplified and he better be able to test it if he is going to pull out a ticket book.