i've done this, and though i took some pics, i haven't had the time to find them.
very simply, you must take apart the center console and remove the roll hoops on either side, and take out the middle piece where the subwoofer sits. follow instructions on roll-hoop retrofit on mz3.net
then, push up on the bottow of the roof liner to separate it from the metal cage in the middle.
go to the trunk, and remove the back liner (grey) from the forward part of the trunk. on either side, are two grommets with lots of wires. i would feed all audio cables on the driver's side as the passenger side carries the (+) battery lead, and can induce noise.
from the cabin you can feed the wires directly through to the grommet hole (some 2-3 inch hole) on the driver's side....
i ran 3 pair micro XLN rca cables (monster cables), and have no noise. i also ran a 4 pair and 2 2-pair extra cables for upgrades in the future (to carry low-impedance electrical signals...)......
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