you trying to top mount them or bottom mount them
its not about that.. what im doing is cutting out about 90% of my rear deck and then using a big ass piece of expanded steel wrapped in speaker mesh to simulate a stock rear deck.. then build a box that bolts underneath it as snug as i can get it ,there is alot of countour so it wont be "flush" but itll be as close as i can get..and it really wont matter because its gonna have the whole rear deck as a bid ass trim panel... so there will be 3-8s or 3-10s and 2 6.5s in the box.. and the box will be the entire width of the rear deck and as deep as the rear deck front to back.. but as shallow as possible up and down..
So when you look at it from inside.. it will look stock..
and when you look at it from the trunk it will look stock and be wrapped in stock carpet.. the only thing that wont look stock is there will be a 3-5 inch drop lip where the box hangs down..