Depending on when the tank was built, there are as many as three things you can reasonably do; the corner reinforcement, the vent, and adding the new fuel gauge. We have two 12s, one flying, and one ready to fly. We are doing all three, and you might consider doing all of them while you are at it. All will add value. Actually, the reinforcement isn't all that big a deal, as long as you pay attention to possible leaks. I would look at it as basically mandatory. The vent is a safety issue in that you can get water into the tank with the early system, and the new gauge should make checking fuel level easier in bad light. Your call...
Bob
