I just finished installing my new head unit and amp into the stagea. took me a while but i don't have any wires showing what so ever. it's really a rather simple job, you just have to be prepared to pull most of your interior trim out to hide the wires, same as you would in any car. i ran the power cable for the Amp down the inside of the front right quarter panel straight to the battery, and it goes all the way back to the amp, which at the moment is just sitting in the boot. i'm rigging up a custom sub box in the next few weeks, which i will take photo's of during the install.
My plans are to have 2 x 10" or 12" subs plus the amp sitting in a box which deosn't look outrageous, but does the job. will keep every one informed if anyone wants/needs to know anything about stereo installs