Check the following brands for front stage:
CDT
Boston
JL Audio
Polk Audio
Alpine
Focal
As for the rear and the lack of a sub, loose the 6x9s, you don't need them, then get a pair of 8" subs. Problem solved.
I would seriously look for a set of 3-way components... or make some...

I have a feeling that a nice 6.5" midbass in the door and a pair of something like 4" 2-ways in the dash would rock and rock great.
One other thing, the doors on a C4 work like a 160hz resonance chamber. You will want to deaden the doors a bunch and perhaps even get a notch filter to bring that frequency down a couple of dB.