Put it this way. I had both a chip and a Viper fitted to my 172, and the Viper has been removed and thrown away and the chip is still fitted. I wasn't able to do a before and after dyno of the chip, but it felt better with the chip fitted right through the power range, and I got measurably better quarter mile times. Whereas with the Viper I was able to dyno it before and after, and the dyno said the difference was so minuscule that with all the extra noise it generated I pulled it off and threw it away. Of course you make like and value more noise.