This is what we started with. A pair of 4" speakers firing straight up into the rear deck and a 6" woofer.

First task was to build the basic shape of what I wanted.

Then I stretched material over the frame until I got the desired shape. Then fiberglass resin was used to keep the shape. After that I built it up in layers on the inside to get it to the desired thickness.

Then I sent it off to the paint shop to be sanded, primed and painted. Special thanks to J&L Autobody for the great paintjob. What we ended up with is a set of Crossfire SR5, 5 1/4" separates and a Crossfire BMF 10". The 10" fires back into the rear wall of the passenger compartment. The 5 1/4" speakers are recessed and the grills are countersunk to achieve a factory look.

The final result looks factory. I had several people that did not see the work in progress ask what part I built.