If you're thinking about stepping up to Zapco Comp amps, then you might want to consider better components, like Seas Lotus, Morel Elate, Buwalda Hybrids, or perhaps Zapco's components.
Excellent components for less money, would be Oz Audio Matrix Elite, Phoenix Gold Ti-Elite, Polk SR6500, or going fully active with a variety of drivers from Seas, Scan Speak, Morel, Dayton Reference, and the above mentioned brands.
Other amps to consider, DLS Ultimate, Arc Audio, Genesis, Audison.
Subs, Soundsplinter, Image Dynamics, Seas, DLS, Peerless XXLS, Dayton Reference, TC Sounds.
It basically comes down to your total budget and what you want out of the system. 2-way or 3-way front, passive or active, etc. etc.