I have the 24 gallon which I installed myself. I've got an older Kaymar rear bumper and it fits fine on mine. But I remember hearing there were some fitment issues with the 4x4 Labs. Not exactly sure what they were, but I'm guessing from my experience. Do you retain the stock tailpipe behind the rear axle with the 4x4 Labs? Because if routing is modified, (towards the center of your rig,) it will interfere with the tank. Also the rear of the LRA tank bolts to a bracket that is added to the frame near the rear crossmember which I believe is modified or removed during 4x4 Labs install. @wardharris should be able to give you more info. If he doesn't reply, try messaging him.Anyone know if the rear auxiliary 25 tank will fit with a 4x4 labs rear bumper? 24 gallon
Rear tank mounting bolts & spacing on mine:
Stock exhaust clearance near front of tank:
Also you can get an idea how low tank will hang below frame:
I've got a dent already in my 24 gal & not from rock crawling, so if you pull the trigger, be careful.