I ended up replacing all 4 woofers with a new set at the same time as I modified the enclosure. So after some major upgrades and break-in, Ive hooked up a 250w @ 8ohm amp and almost cried when I heard a proper kick drum for the first time. Wow, it is so good. The top end was a bit bright with this particular amp so now I'm going to try bi-amping with a miniSHARC for a crossover. It's going to take some time tho.