[GhettoPop]

i got a set of march underdrives. not a huge gain, but i did feel a LITTLE something. i also have a pa performance alt. although the stock voltage gauge drops a decent amount with lights on and sitting on the brake pedal, no charging issues. the UD's work by providing the alt with a smaller pulley, thus turning it less and robbing the the engine of less power. the pulley that came with the pa performance alt was smaller than stock, and the march UD pulley was even smaller. march also makes a "power and amp" kit which comes with a larger alt pulley. if your really concerned about charging and dont want to spend the dough on an alt, buy the UD kit but use the stock alt pulley and your should be fine. if a UD kit gives u 10 rear HP, leaving on the stock alt pulley will give u 9. u can even buy a bigger pulley for more charging