Armageddon actually didn't supply a map sensor at all, so I still had the stock 1 bar sensor. I could have definitely got by with a 2 bar sensor as they will read up to almost 15 psi of boost, which is way more than I'll be running, but summit Racing had the gm 3 bar sensor in stock and they have a physical location close to me and I just picked it up. Yeah, the higher the bar number the higher the pressure sensing ability of the sensor, and they read in absolute pressure which starts from a total vacuum. Standard ambient pressure at sea level is 1 bar or about 14.7 psi. So essentially a 1 bar sensor will only read a vacuum, a 2 bar sensor is good for just under 15 psi, and a 3 bar sensor is good for about 29 psi. As a bonus, when I end up building a forged engine at some point, I'd like to turn the boost way up and make some really big power, and I can just keep this map sensor. That's a long ways down the road though Sent from my SM-N950U using Tapatalk