To me 25% isnt much. Cause im sure just normal driving your battery isnt just being sucked to nothing unless your headlights are on. If your wanting power you'll turn off your AC... so 25% of alt, and water pump, and power steering which you wont use in a drag either ... so im sure its not much ... will probably be best for low end power IMO
smaller pulley means more boost. But I understand your logic, you cant get bigger than the stock m112 blower pulley, only smaller, so using a UDP will bring the stock boost on a v6 down from around 10-11 psi to 7-8psi with a 25% UDP bulley kit.