I need to have a driveshaft made for a 440/4 speed Duster that I've been working on.What is the advantage of using aluminum instead of steel? Many newer cars & light trucks use aluminum shafts so there must something to it.I read about a dyno comparison between alum. & steel shafts & they claimed that with the alum shaft the car made 10 more HP at the wheels! I'm skeptical about this ,but if the OEM's use alum. then maybe there's something to it? Any opinions or experience on / with aluminum driveshafts?