There are those out there who believe in putting home audio loudspeakers, mini monitors of course, into their car. read below
"The LS3/5a I can also see somewhere in the passenger dash.
Likely the Quad II's would have to run in the front trunk (bonnet)
with forced air cooling (ahh, a return to Porsche principles) and of
course some type of inverter/converter supply for the mains power.
The trickier part is creating some type of folded conjugate load AB1
enclosure that could take the rest of the bonnet space. You can
then "Pipe" in, literally, the output of the port into the passenger
compartment. Before you laugh, a similar process is being done
already with the subwoofer on top of the emergency spare. However,
other fast woofer systems, like Paris Audio's dual 5" Focal system or
single 8" JL Audio system in the passenger foot well, there is more
than enough low bass and especially well integrated to the satellites."
This quote was taken from a LS3/5A yahoo group.