I like my airbox without the X. It's easier to see through it without it, but at the same time, if I did have an X I'd get a tank bag, but I don't since I'm worried about scuffing it all up. Makes me look forward to the day when I have another bike with a metal tank so I can just slap a magnetic one on there.
I wish they made more transparent firebolt pieces as well, but I assume the extra weight might make it likely that they would crack in too many places.
I also wish an aftermarket company would start pumping out some other colors like green or a lighter red, even pink. I'd love to get some clear ones with no color tint as well.