You should verify this yourself but I am pretty sure this is the requirement in Michigan
"Noise levels will be checked from a twenty (20) inch distance at a 45 degree angle from the exhaust pipe at half the vehicle's rated RPM's or as detailed in the automotive specifications SAE J1169, March 92 or SAE J1287, June 86. The maximum noise level permitted under these testing conditions will be 94 dBa which is the current limit set by the Off-Road Recreation Vehicles Act of Part 811 of 1994 PA 451 (MCL 324.811). All vehicles will be required to have a muffler and spark arrester containing baffles that can be confirmed by inserting a flexible, plastic rod."
Keep in mind that for every 3 dB increase in the SPL, the sound energy DOUBLES. So 97 dB is twice as loud as 94 dB. The FMF "Q" system w/o the powerbomb meets the 94 dBa spec, with the powerbomb it test at 93 dBa most days.