Ok so I just got my 300c its a 05 it says boston on door by mirror and it has a spot for sub in the rear deck not sure if I have a center in the dash yet. I have just a basic cd am fm oem in it now plan on putting in a double din pioneer but waiting on nav dash to arrive. Besides pulling grill off center speaker is there any other way to know if I have 6 or 8 speakers secondly im installing a JBL MS-8 as of now my plan is to by pass factory amp and use exicting wires and simply putting ms-8 in factory amp location with slight mods my question is what is everyone using as far as factory retention of the wheel controls and display in dash. It sounds good now but I noticed it sounds as if the doors are the drivers and dash is highs?? Has anyone made a custom box and used the existing sub hole as a blow threw so you dont have the poor sound with back seat up??