lol have you tried one? it has a full refund with shiping if i dont like it... but last time a seller said that and i returned it they sent it back and said i broke it lol. but this one has a lifetime warranty so if i did break it they should still cover it... but most people dont know how to check to see if they gained hp... i dont have a dyno or know of one that will do it for free or cheap so i guess ill just save my 10 bucks ha. but i thought it was funny that alot of people has left positive feed back on this item.