^^^ maybe a *bit different because it serves the same purpose correct? the difference is what? they build it in to a wiring harness for you to fit to ur alt so u dont have to splice any wires..... I mean if ur just tricking ur alt to bump up the voltage seems like the same thing to me.. ----------- crunkjuice. yea some cars are pcm controlled, meaning the cars computer controls the voltage, usualy newer cars. my girls grand prix has pcm controlled alt and the voltage is all over the place, sometimes 13v sometimes 15v... she doesnt have any amps or anything the only thing that pulls the most amps i can see is the traction control, slam on the gas and it cuts on and voltage drops to 12v easily.