[aznatama]

I forget the costs of the OFH, but ceramic coating a one-off item is likely to significantly close the price difference between just purchasing a pre-coated header from another tuner.

Also, is OFH catted? don't you have emmissions on MD? all considerations to think about since you don't want to be swapping every year or get cited by police.

1. Yes, I would get a coated header. More stealth install, lower maintenance, and arguable lower engine bay heat
2. Header is relatively well protected due to skid plate, but I guess some stuff could make it past the radiator? I've had no problems yet.
3.
4. I would do inside and out. IMO, why half-ass it? Although, I'm not sure if there are benefits to be had doing inside and out vs just outside.