Blue,
No problem posting your 2 questions, here in Ham Radio, but you might also check the Explorer Audio forum as well, for the FM antenna question. I'll still give my $.02 about the FM antenna as well.
Generally, since auto stereos are normally set up for unbalalnced antennas fed by a type of coaxial cable, a "band tuned" 1/4 wavelength verticle antenna of approximately 30" works well, and that's exactly what Ford supplies with your EX. Just be sure that it is in good condition, the cable is good, and is plugged in securely to the radio. The next option, is to get a "fm booster" module that plugs into the antenna line and is really a pre-amplifier that increases the signal level to the radio. Auto sound stores, JC Whitney, even Radio Shack carries these. I wouldn't pay much more than $20. I haven't ever used one of these persoanlly, but might be worth a try.
As far as the coax length for your CB. the length only matters if you are running "Phased" dual or multiple antennas (sometimes you'll see 2 identicle antennas, one on each side mirror, of large trucks). Otherwise, the shorter the better!