Amplifier Placement, Base Model

I have seen quite a few discussion threads with respect to replacement speakers, but nothing yet on amplifier installation for the base (non-Bose) model. I understand that the factory head unit is only rated for 5 watts RMS, and was exploring the possibility of adding an aftermarket amplifier in addition to replacing the speakers. It seems that there are a variety of good 5-channel amplifiers on the market today (Eclipse 3650, Soundstream P205, Alpine MRV-F357, etc.), and that only one amplifier would be needed to drive the front speakers, rear speakers, and the subwoofer. In looking at the factory service manual, it seems that in the Touring Model, the Bose amplifier is placed on its side inside the console that houses the transmission shift lever.

Has anyone attempted to install an aftermarket amplifier in this location?
Are there any other locations that would be unobtrusive?
Can one replace the subwoofer amplifier with the 5-channel (if the sizes are the same)?
Does anyone have experience in installing aftermarket head units that are higher powered than the factory head unit?