Just another opinion:
I have Boston Pro Series components in the front doors, Boston 5 1/4" in the rear and a 8" JL sub in a custom made box that I put behind the pass seat. The box is almost invisable (and it is very easy to remove) as it is covered in the same carpet material as the Porsche. All of this is powered by a Kenwood Excelon X817 which flips over (automatic) when not in use- it looks like the face was removed. The 817 controls the Kenwood amp... a 501 (4 channel, 300w) and the whole system sounds fantastic. I had the amp mounted in the trunk, close to the battery which helps with power delivery and wire routing. The 817 powers the rear speakers only, the amp powers the components and the sub. I can be cruising down the highway at 80mph with the top down and the stereo sounds clear and loud.
