What Dynoman said. Erics 5.7 chip...for racing...requires you to monitor temp/humidity from run to run. As an example, when I was bracket racing my car, it would pick up 2.3 tenths on a 15% humidity drop...which means it got leaner. If you're riding a fine line already, then without manually adding high gear fuel, then you'd go lean and be into a set of heads gaskets. Erics 6.1 chip is the way to fly for most who wanna race using his chips.