I would call trialseven they have incredible customer service I had a few questions on a couple of different audio installs on broncos and they have always helped and sent out any replacement parts asap whenever I had issues
Not without a check engine light cobb got massacred by the epa and you can no longer do that on their devices, that’s why I never updated the cobb on my focus rs
The tailgate mounted enclosure have some l hangers that go into the vents in the tailgate to align it and they use 4 rivnuts straight into the tailgate to hold them
Go with a 0 offset to future proof yourself, it will allow bigger tires, different coilover/control arms and the biggest thing the ability to do a mid/long travel kit
Completely up to you it’s a good system but in an audiophile and go crazy with all my setups if your close I’d give you a crazy deal to get it out of my garage