I've had a small amp for my 10" bandpass inside the side rear body cavity. It's accessed by removing the storage bin that's next to the back seat. It was easy to run wiring to this area from the dash and to the bandpass behnd the back seat. Profesional - no, but it's been working fine for 5+ years now. I used foam to cushion the amp so it doesn't rattle around, and of course sealed off electrical connections from shorting. I would not put a huge amp in this location because there's no airflow but my two channel dodge charger 100w or whatever it is has been fine.