Tater, you should do just the opposite. Put the mids/tweets in the kickpanel and the 8" in the door. The 8 will be acting as a subwoofer of sorts, in the system you describe. The sound will be somewhat non-directional, dimininishing the main advantage to a kickpanel system.
As far as waveguides go, I wouldn't mind them, but if I got them, I couldn't drive the car since i would not fit. My legs are right up against the dash with the seat as far back as it will go.
