what amp?

The USAmps and the Memphis are the ONLY ones I would even consider from that list. Memphis certainly the best of the list. The Eclipse mono Class D amps are very nice, and the Alpine PDX1.1000 would fit nicely into that category as well.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Kicker Zx 1000 or Zx1500

What speakers are you driving with this amp? How much do you want to spend?

us amps are still pretty good, Memphis is def nice. I LOVE te new Zapco stuff, esp. the DC stuff. If you havn't seen it, it is amazing. not shure if they have enough juice for ya though. an 1100.1 with drive the shyt out of 4 Infinity Perfect Var. Q 12's though.used to be loud, used to be fast...now I am married LOL

don't mention zapco to the guy if he's trying to keep his wallet in one piece! haha

If you're looking at the US Amps XT series, keep looking. They won't do their rated power. Apparently the techs there think they can defy Ohms law The MD series will do rated power. I usually am against mainstream brands, however, I have to tip my hat to RF. Their new power series amps are brutes. Very underrated and stay cool. The Alpine PDX is a great way to go as well. There are so many companies to choose from. Personally I dont like Kicker amps. They are good with current draw, but don't seem to be near in the league of RF. I had a Treo SSX 1500.1 (rated at 3,000w @ 1 ohm, but there is no way the amp actually did that, was probably around 2-2.5k and it outperformed the kicker zx 2500.1. It drew more current, but on the exact same setup it was nearly half a decibel louder than the Kicker. I had to max out the gains on the Kicker as well. On sine waves, there was no difference between having the gain set at a tad above halfway or all the way up, it was quite odd.