i've had them on for two weeks now. theres a good power boost at 3k and up and the throttle response is improved. the electric fan should help more on hp and throttle lag. i had mud and stones packed into each of the holes, had to use a tap, brake cleaner, an air compressor, a punch, a hammer, and screwdriver to get the puller holes cleaned out.. it took about a whole day lol. I was going to install an Overdrive alternator pulley, but the voltage levels seem fine to me.
also, i'm not sure if the UDP's helped, but my rpm's at 40mph are about 950 and my rpms at 70 are right around 1750-1800