A lot of responses on installing a radio on the old 444/544 models with several comments on trying to hear it over 50 MPH. I placed some stuff used for roofing called "Ice Guard" over my new floorboards, hit it with a heat gun and it bonded very nicely (it is rubber about 1/8" thick) I then put 3/8" felt padding from the firewall all the way back to the trunk, then carpet. Inside the doors I cut a piece of high density foam about 12 x 24" and cemented it to the center. That reduced the "Tin Can" noise from the doors. My vent window weatherstrips didn't seal worth a darn and I cleaned them real good, put black silicone in the channel then placed a piece of Saran Wrap over the silicone, closed and latched the vent window. You have to wait several days for it to cure then carefuly trim it with a razor blade, open the vent and peel off the saran wrap. The result is a seal that matches your vent glass and chrome frame very nicely. Be sure to pull the wrinkles out of the saran wrap when you first set the window. The car was very quiet and well worth the time it took to deaden it. Hope this helps someone out there that would like to hear their radio above 50 MPH.
Dennis