yea they dont do any thing... a friend or mine actually got one of the 60$ ones and put it on his Nissan frontier and he actually uses it on a daily basis and says that it dose something... but all i think it dose is waist battery life and make a crappy wine noise when it is on... and at idle i had him turn it on and it sounds like someone is putting their had over the intake... and sounds like it is going to die... but he thinks it is from the extra air it is getting... lol but i wouldnt waste my money... just like spending 20$ on a resistor to put in place of the intake sensor that tricks the computer into throwing in more gas in even tho it dosnt need it (and probably dose more bad then good)... that is one i wish i would have thought of... i could have make MILLIONS!!!!