I mounted 2 amps and a sub directly below the package tray in the trunk. The 68 has a rise there. All three are lined up and a sound board was installed to hide everything and give it a clean look. Spare is tight but fits.
I have one on the underside of the package shelf for the rear and another in the glove compartment area for the front. Yes, it renders my glovebox useless. But I already mounted the controls for the air-ride suspension there anyway. So it wasn't much of a loss to me.
Im running my speakers off the head unit. everything sounds amazing already. running the sub off a mono amp in the trunk. sitting on the gas tank right now but will be building a custom box and tucking it all right under the package tray also. With the hum of the motor and cruising with the windows down constantly (california weather) i dont see a purpose for putting more money than needed by adding another amp to run the other speakers. and i dont have the money for it haha. but everyone is different. plus i forked out a little more on the head unit in the dash to get better sound. Everything is loud and clear for me.
by the way does anyone have any pics of the box they have to go under the package tray? im just running one 10' sub. would like to see an example if possible before i have a crack at it.