you want suggestions?... look at the setup I just did:
i posted it in the civic forum but i'm just copying it over... i just hashes and a piece of plywood underneath to screw down that amp and 2 hasps. doesn't move around at ALL. and i can remove it in probably 1 minute
1 12 will move around a lot. esp if you have the amp connected to the back of it. that was my setup before i've had it ROLL. tip, roll back and slam against the top of the trunk (i drive kind ahard).... anything will make 1 12 box move... 2 12s and you probably won't have that big a problem.