i got mac underdrive pullies and i kinda dont like them because they have made a squeekin noise ever since i got them so and yea, dont get mac. i wouldnt mind gettin some steeda ones but there expensive. so i said go with steeda or asp
i had the mac pullies and my battery would not charge. i did have some resistance in the alternator wiring though.. i rewired it and battery still would not charge. put the stock pullies on , battery charged and no noticeable horsepower lost. for my daily driver, as mine is, id leave stock ones on. only about 10??? horsepower difference.