Great topic!
Already I am jealous, as I have a convertible and cannot put 6X9 speakers anywhere!
I just finished installing my 6.5" speakers in my new kickpanels, and they look great. You can find them available with or without the speakers installed. I bought them without, since I already had the speakers, but be warned you will need a good scroll saw to cut the holes. Here is a link to the kickpanels:
http://www.mustangsunlimited.com/ite...sp?T1=KMCIN+01
Actually, those already have the holes cut. What a deal. They are $65 for the pair.
Also, there is the opening on the top of the dash where the original 4X10 speaker was, and you can replace that with:
http://www.mustangsunlimited.com/ite...asp?T1=DS15+01
for stereo sound. I haven't gotten this one yet, but it is on my list.
So there you have it; six speaker sound and it all looks fairly stock, or at least tasteful.
Good luck,
Michael
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1966 289-2V C-4 Convertible. All original drivetrain. Factory center console and power top. Dual res. MC and power brake upgrade. Rust bucket brought back to life, I am the 2nd owner of "Lucy".
1990 GT 25th Anniversary 5.0 AOD Convertible. Dynomax cat-back, K&N, the usual crap. Welded in subframes, welded in reinforcement plates (Ford riveted them in. Go Ford!

)New engine and transmission. Date coded radiator hoses. Second owner of "Katie".