I've owned two former police cars and had fun in them both (a cross country speed run, for example, and we never got pulled over.)
That one was a CHP captain's car, with low miles, cloth upholstery, no push bar or bad guy cage, and hadn't been thrashed (until we got our hands on it.)
Sold it later to Dan Aykroyd. True.
The other was a L.A. Sheriff car that'd seen a pretty hard life, but not as hard as some. It creaked, rattled, burned oil, and smelled like a combination of body odor, stale coffee, and piss. I took it to the self-serve car wash and power-washed the entire interior for about 30 minutes. That helped a little.
Richard, your point about not wanting to look like a cop these days is sadly true in more than a few areas.
I'd take a Town Car hands-down, for my daily. My favorites were the old square ones from the '80s. $29.95/day from Budget and you were riding like a king.
Put a supercharger on a newer one like you're considering, and you'd probably have a pretty fun luxury machine.