the old school soundstream, i.e reference and rubicon models are one of the best amps ever made. the spl xxx subs can really put out some sound also. i dont have much experience with the newer amps but i've heard mixed reviews. stick with the old stuff and you cant go wrong.
i own a sound stream rubicon 1000... i had it hooked up to my boston z6s and they sounded great... just replaced some of the internals, had a few transistors and resistors that weren't ohming out right... but now its better than ever and kicks a$s all the while.