I've got Infinity's in every door. It took a little cutting and a 1/2'' thick plywood ring in order to clear the glass. The 3.25'' mounting depth sounds right.
I got mine from
CarStereoTime.com. $165. MUCH less than Crutch.
BTW, they need their own amp in order to sound good. In-dash decks just can't drive them properly.
HTH,
BP