I'm going to install 3 amps on the overhead i have an idea of how i wanna do it but i was wondering if anyone has ever looked under the celing cover at the actual metal and if there are any braces there of if it's just one solid sheet????

 

You will probally want to make some type of a rack. It is most likely not smooth under the ceiling, and if you put a screw throught the roof your gonna be pissed.

 

Ther is cross bracing but you have to pull the headliner so you no exactly wher it is use rivots to mount extra steel for a rack enjoy