I work at CarTunes Sound and Cellular - I've had a few demo systems in my old Golf, the loudest being 4 MTX T7000 15s - but now I've toned down, and am planning a Focal/Dimension system with 3 10s for sometime next year, after I get all the other stuff on my list of mods done
This is my buddy Jimmy's 240SX - 2000 hours of labor
Pictures really don't explain how amazing this system is. EVERYTHING is motorized, even the tweeter mounts
There's 2 video screens, DVD, VHS, full Nav, PS, and many goodies. Total cost to reproduce this system for a customer: $100,000 US