Looking for great 4 channel amplifier?

I looked at putting Kappa's in my car a few years back too and the sales man at Crutchfield said they were really watt hungry, so you should consider getting a good amount of watts, which I think you have. I would go with the JL. It has really good customer reviews and they have a great reputation. Plus it has the highest output of the original three. I don't know too much about JBL amps so it could be a good deal for the money. Check around e-bay for new amps too, there are some good deals. The pioneer seems like overkill. Unless you plan to Dynamat your car and rewire all the speakers, I doubt you would notice a difference.