That sucks man. I had collision only on my Silverado 3500 and a tornado knocked down our barn on top of it! The cool thing was that I threw it in 4 low and blasted through what was left of the barn and the truck went to work that day - I regret not getting that in video.
My understanding of those rear quarter panels is that they are spot welded in place. Maybe you can find a wrecker and pull the quarter panel off if, then have a shop weld it on.
In terms of the paint, Arctic silver is super freaking close to the same silver that Nissan uses on all their cars. Like it's so close that you can only tell 6 inches away with the two side by side (please note that my car hadn't been washed in about 18 months and the wrap was brand new in that pic. After a week of driving the difference was it impossible to notice lol). Look at my headlight mod pics - that wrap is Nissan silver. You could have a good paint guy use that color and blend it to the remaining panels. I'll bet you a nickel you'll be the only one who will ever be able to notice.
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