i would vote the two sundowns. BUT the 2500's were not made by zenon, i believe, and im basing this off my zenon 1500s. i ran the saz1500's at .5ohm strapped rose to ~2.3ohm and got a 150.4. then i went to two zenon 3k's at .5 each and gained 1 db. so i think the lower impedance helped a lot. you just cant be mad if you smoke them.