I just did this myself.  I removed the stock speakers and cut all of the
"speaker" stuff out of the housing..I got a pair of Blaupunkt 3.5" 2-way
speakers, cut off the mounting tabs, and used PVC cement to glue them in
where the old speakers were.  Now I have good speakers in the factory housing
and my window cranks are operable.  More importantly, I also replaced the
rear speakers in the AC housing with 5.5" Polk 2-ways.  I fade the stereo to
favor them, better base response and I can still talk to my wife.

Bill Marshall
85 GL Tiico
Phoenix