I agree on the pager issue, plus they eat batteries
the audio however.......
the town car has an amplified jbl/ford system in it
if it has a small square amp plug on the back of the head (grey cable)
all you need is an upgraded head unit and a sub/amp combo
the new head unit when connected to the factory amp is WAY loud
if this aint enough "words in your mruzik"

you can add a pair of tweets up front
if you do this ........the adapter for the ford premium sound
does not have a connection to the cable's shield,
so if you have ignition noise, you can connect a ground wire
to the braided shield of the grey amp cable. (trick metra dosen't even know)
as to amp/sub a single 12 or dual 10s on 350-800 watts is enough to feel
but a combination of 8's or 15's would work well depending on your music tastes
I am not into brand bashin' but the MTX line has given me plenty of headaches
I even called mike at the tech dept in MTX, to tell them how to fix the remote circuit
that caused the amps to draw current through the remote lead, if hooked to ignition
(the 800D) predecessor to the 801 that dude ^ reccomended. I have done this shizz over 20 years
that line will never be on my shelf again.
they have a crappy line, you will blow that shiat faster than a $20 in da' hood on friday
there are plenty of options out there
I would take it to a shop with certified installers
and years of experience, or you will get a hacked up job