Full audio upgrade for a T4 Trooper

Hi,
I want to upgrade the audio in my T4 Trooper.  This will include a new headunit, front speakers (including adding new speakers to doors) and new rear speakers.  Probably to include an amp and poss a subwoofer too.

Has anyone else done this with a Trooper? If so where did you mount the rear speakers? I think I can probably mount the amp under the drivers seat, but again, has anyone done this?

If anyone has pictures of rear speaker mountings that would be a great help,

Thanks
Dan