FWIW, I cut out the rear deck of my old GTI when I was in high school and dropped in 6x9s cause I thought it would be cool to have big speakers back there. After a while I found that 6x9s are a bit overrated, they were decent, but you can get great speakers that will give you as much volume and better sound that will fit in the factory locations if you look around, and its a lot less work. Unless all you want is people to see "wow there's 6x9s dropped into holes in the back of that car..hella custom y0".