I have no input on gas tanks.
I do have input on auto trans. If you run a stock dipstick make sure to get a newer model one that is sealed well, or you will spill on roll overs. My constant issue was with the auto trans vent. I had issues driving no my side and super steep climbs. Believe it or not, I also ended upside down pretty much every time wheeling. I tried every check valve, hose routing, and nothing works when you are upside down waiting for a friendly winch line. I ended up putting in a ball valve mounted close, so I could just shut the vent off during the consequence of my stupid entertaining decisions.