I ran them for a bit. Sold them because the did nothing and I wasnt getting enough water flow from my WP. Serious waste of money. That goes for any pulley for that matter.
Not turbo here, no probs with wp flow or temp, no alt issues. Have the medieval wp,alt & ps pulleys & UR UDP. No big blast difference but I'd say being lighter has to help. NA sportauto needs all it can get. lol.