2 comp sets wouldn't hurt. I have ran Pioneers top 6x9 4ways and liked em. So if you're set on 6x9s go with what you want.
As far as amps...theres so many to choose from. Personally I've only had a few 4channel amps.
An Alpine, PPI, and Power Acoustik and they all performed well. I would even prefer Sony over Crunch.
You can build mini boxes for the rears and it would help a lot.