To remove the dash pad there are screews that need to be removed from the defroster vent, also under the front lip. After you remove them just pull the cap away from the windshield the front is held on with clips.
I removed the dash and just as thought there were no speakers there, just a blank cover. I removed the covers and cut holes in the to fit my 4 inch infinity speakers and ran wires. It deffinately ads a deminsion that the 6½" and 6x9"s couldn't add. Sounds great. I have one Mutt of a stereo system in my car with infinity in the dash, Panasonic on the door, Kenwood in the rear and a pioneer deck.
I have found that Pioneer makes a hell of a head unit but lacks in their speakers. Kenwood 6x9's are the best for convertibles. They tend to give more loudness with clarity. The Panasonics well they were just very cheap. and lastly Infinity makes a great small speaker but larger speakers tend to blow easily.
good post, I have to remove mine as well to get to the delay timer that is buggering up my dome light. I didn't realize there were no speakers under those grills.
From what I hear, if your car had the Bose system then you will not have dash speakers. Don't exactly know why but thats how it is. After removing the dash to install the speakers where the old spot was you will have to make some modifications. I actually cut the black plastic blank and mounted the speakers in that area. I am sure that if you do it right you can easily just recover the speaker with the screen given. I chose to leave mine open.