Seriously, that car looks like a great candidate for removing the head unit & adding the empeg and and a head unit (it looks like a double-DIN opening). If you fed the empeg to a head unit with an internal amp (which would also get you a radio if don't have a tuner module) then you'd not need an external amp and you could probably get a harness connector that connected right to the Volvo for the speaker & power lines.

This would be very easy for a pro-installer, since there'd be no remote amplifier. The only thing would be connecting the switched and permanent power wires to the empeg. The only other connection (other than ground) would be connecting the front line outputs to the input on the commercial head unit. When you're done you could have tape or CD, Radio as well as you empeg.

Keep the empeg, and ditch that POS factory radio!

-Zeke