3.5" stock, you can probably fit 4" in there with a bit of trimming. Note that the stock speakers are part of the grilles, and you will need to cut them off if you want to use the factory grilles. -- Dan Simoes dans@ans.net Worldcom Advanced Networks http://coimbra.ans.net/dans.html 100 Manhattanville Road (914) 701-5378 (voice) Purchase, NY 10577 (914) 701-5310 (fax)