i been using unorthodox pullys on my cars and customers cars for
the past couple years, without any problems, with the undriven pullys you will get you lights going a little dim at idle, but unorthodox makes most of the pullys now underdriven or the same size as the factory ones.other than that its all good.
Other than that, nothing. And personally I find it to be nice. People sitting across from me at intersections are less likely to flash their highbeams at me when my lights are dim. Tap the gas and they go back to 80 watts of pure joy.