If your referring to the Dolby center cover, than the following applies:
The outer cover is held in place with clips at each corner. You have to carefully push in on the clip as you lift the grille at each corner.
Once the grille is removed there are 2 torsqe screws and 2 clips which hold down the speaker assembly. Loosen the screws and the speaker assembly will come out, the clips come out easily. The new speaker will cost you $96, and it's hard to tell the differance. I eventually replaced the SC-900, and lost Dolby as a result, but the sound is much better!

Spence
98 R wagon