Noob--Used K2 400E setup taillight, tires

[Buddahbelly]

Hey all, just got a "plated from the dealer" Baja Designs 400E with about 1400 miles on it, mostly offroad from the looks of the damage. Installed a new battery and BD headlight setup. A question I have is about the rear fender-- the one bungeed on there (with taillight and license plate holder) has no obvious means of screwing it on, and I want to get it inspected in PA. Has anyone stuck an acerbis on there, or anything else I could find online? Also it has Pirelli Rallycross knobbies on, and I am planning on riding it mostly on road. Any suggestions for a good, forgiving street tire in the wet would be appreciated. I don't mind the deathwings on my DL650, and I don't ride aggressively so much as just "poorly." Thanks, Shaggy