So I'm wondering with hard off-roading and body flex if the topper would ever get into the cab?
It will scratch/touch the top of the bed if you rail some hard hits. (i have a leer xl)
Ask me how i know..
It isnt that bad, it wouldnt stop me from my normal offroading one bit (trails). On the high speed stuff i would be a bit more "aware" and a few times i thought "********, you have a topper!" but nothing bad has happened yet beyond some scratches and the burning sensation of stupidity that comes with forgetting you have a topper on after you hit a jump.
I think the worst was when i decided it would be fun to jump a few soon to be built housing pads. I had to check to make sure i still had a topper on the back (i did, thankfully). After that day it hasnt been so hard to remember its there, but it is still a struggle sometimes.