i have bad nwes and worse news for you.shortly after i got my z-28 -also a 99 i blew the same speaker.bought one from the dealership.1 speaker cost me 80 bucks.i suggest a junkyard or ebay if you want to go back stock.also getting the door panel off and back on is loads of fun.

 

Yeah man its a pain in the ****, I broke one of the clips taking the panel off... but once you do it, its not that bad, ended up installing some infinity components... took a few hours, but i guess its worth it.