I know you said this, and you wrote it like you've heard this before, but...

Replacing your speakers will have a bigger effect on your sound than adding in a new amplifier. A more powerful amp will give you some more headroom for dynamics and pumping up the volume level a bit but it won't really change the tonal quality of the overall sound. A new amp may make your sound "brighter" or "warmer" but the overall characteristic won't change. (Boy, did I just repeat myself, repeat myself, repeat myself, )

Vocals exist in the mids of the frequency range. A speaker either reproduces this range well or it doesn't. There's really no way around this. It's physics...

Outlaw's a great company and it's a truly amazing sale. You can always do the trial period if you want hear the difference the amps will make. IMHO, you'll be speaker shopping after that...