mach 460 rear speaker cover removal

I believe that whole rear deck comes off, not the speaker grilles. You might need to remove the rear seat.

fold down the rear seat.
unbolt the 3 (7mm i think) bolts that hold the rear headrest thing
pull up and remove rear head rest peice
remove to push clips that hold down the carpet on the rear deck which are exposed afer removing the rear headrest

now the semi tricky part, you can now pull out the rear deck but you have to be carefull and bend it slightly up in the middle to get the ends out from under the c-pillars, or you can remove one side c-pillar and it comes out easy.