They're really not loud at all... they're similar to most A/T's in terms of noise, which to make more noise than the stock highway tires. Corey is just sensitive
The rubbing you'll get without spacers is due to the tires hitting the body, not the pinch weld.
You won't have an issue with the pinch weld until after the spacers are on.... so if you want, you can forego the pinch weld mod and then see if you rub after the spacers are on. If you do, its an easy mod to take care of.
With the weight of our vehicles, the sidewall stiffness between a D and E load range is negligible in terms of affecting the ride. Think about it this way, if you deflate the tires will the sidewall hold the vehicle up? No, the sidewalls still flex.
Going from a P to LT tire affects the ride more so due to the weight of the tires (affects suspension rebound) and harder tread compound. Once your in a LT tire, going from D to E really doesn't isn't going to be that noticeable unless you're also changing size (more weight)