Yeah, the 02 sensor bung makes more sense to me too. Some shops can weld in another bung, helpful if you want to do part-throttle tuning with a power adder. Not necessary for WOT N/A or Nitrous pulls, however, they don't use your stock 02 sensor at WOT anyway.
EJ's Dyno shop in Omaha where I've gone a couple of times, he will tap in and read stuff like fuel pressure and water temperature if you want him to. Pretty high-speed place, lots of knowledge too.