This is interesting as I'm considering the FORM smoked tails. I was curious if there is a minimum DOT brightness requirement from the government but there isn't one that I could find. That actually suprised me as they want to regulate everything else.
Took it in for the annual emissions test so I can renew the registration. It sucks that I'm in one of the few counties in Texas where the EPA mandates emission testing.
Dongar products are available on Amazon.
Amazon.com: Dongar Dashcam Power Adapter (5-pin Type F) for Select Ford Vehicles. Compatible with Mach-E, Bronco Sport, Explorer and More. Built-in USB Power Source, Connects to Rearview Mirror, Easy to Install : Electronics
I also have the MBRP catback and I don't recall the docs saying anything about unequal length pipes on the mid-pipe. Mine was equal length like yours and fits perfectly. I'd do what TeamHippo suggested and install with everything loose to be sure but I'll wager it's going to fit OK.
That sounds like the fruitless search I want on trying to find the rattle.
Try the rear seat thing. There's nothing to lose and it takes just a few minutes.
Just as an experiment, put the rear seats down and see if that makes a difference. I had a rattle that was hard to pinpoint. I thought it might be the rear suspension or the exhaust. It turned out to be the rear seat latches. A little grease fixed them right up