I would have a local custom shop do it for you. I have done a 06
stang with 2 type R. 12's in cavity boxes built from fiberglass in the pockets on either side of the trunk when you open it up at the rear of the car. It sounded sick and in order to get the tire out. all you have to do is slice the trunk liner along the side of the box so it comes right up to the box. I know its kind of a bad description but any good shop should be able to do it for you. It wont be cheap though we charged about $1500 for the whole deal.