I got 5 inch MBRP. At idle outside cab im over 80 decibles, WOT outside cab 93 decibles. After adding MBRP muffler delete, At idle Outside cab 90 decibles. IN THE CAB WOT my meter tells me its 113 decibles. That was with windows closed! Just going from MBRP exhaust with muffler, to the MBRP...