I am using an iPhone 11 Pro with Decibel Pro app and Niosh app with microphone pointed at the trailer hitch opening about waist high 10' from rear of truck centered...
Cold Start:
STOCK: Pro Decibel app Cold start outside 82.7 Max and 77.6 Avg
MF: Pro Decibel app Cold start outside 90.6 Max and 87.7 Avg
STOCK: Niosh app Cold start outside 70
MF: Niosh app Cold start outside 72
Idling:
STOCK: Pro Decibel app Idling after start is 72.3 DB Avg
MF: Pro Decibel app Idling after start is 86.7 DB Avg
STOCK: Niosh app Idling after start is 60-62
MF: Niosh app Idling after start is 62-63
Driving - Holding the phone approximately chest level with mic pointed at chest in Normal driving mode with factory exhaust sound ON:
STOCK: Pro Decibel app 15-70 MPH WFO is 96.1 Max and 89.9 Avg
STOCK: Pro Decibel app 70 MPH cruising is 84.4 Avg
MF: Pro Decibel app 15-70 MPH WFO is Pending Max and Pending Avg
MF: Pro Decibel app 70 MPH cruising is Pending Avg
Clearly my phone / Pro Decibel app is hypersensitive and reads high DB...no way just riding in the truck at 70 MPH = a Lawn mower!
Install - Install was fairly straightforward, first throw away the instructions as it appears they were copied from the cat-back system and has you remove the resonator, this is not needed. Also verify you received the correct clamps as one of mine was for a 2.75" exhaust vs. 3" required. Install time approx. 1 hour.
Here is what I did YMMV
Step 1: 10mm socket remove 2 nuts per side (4 total) that hold the tail pipe hanger at the bumper.
Step 2: 10mm socket remove the 2 bolts per side (4 total) on the exhaust pipe hanger (between muffler and outlet hanger.
Step 3: 15mm socket loosen the clamp for each tail pipe at the connection with the muffler (2 total) and lower tail pipes.
Step 4: 15mm socket loosen the muffler inlet clamps between the resonator and muffler (3 total).
Step 5: 10mm socket remove the front and rear muffler hangers (3 bolts total) and remove the stock muffler.
Step 6: transfer stock muffler hangers to MF muffler, slide on clamps for tail pipes and reinstall 2 bolt clamp to the pipe from the resonator (you have to bend a tab on the stock muffler to remove).
Step 7: line up muffler, insert into stock pipe from resonator and re-install hangers finger tight.
Step 8: line up drivers side exhaust, insert into MF muffler and reinstall mid pipe hanger, reinstall rear hanger finger tight.
Step 9: repeat step 8 for passenger side.
Step 10: starting at the furthest point forward tighten pipe clamps (muffler inlet from res), then muffler hangers, tail pipe / muffler joint, mid hangers and finally line up tail pipes to be even and sit at the appropriate distance from the bumper.
Step 11: Start up and smile!
I have installed several aftermarket exhausts across various vehicles and have found it easier to remove the entire hanger vs lining up the studs to rubber...I will give MF credit the studs for the rubber isolators are right on.
