FormulaNova said.. the ones in the US meant to be cop cars have a really low end interior spec, so its not quite as luxury as you would think from the name, so you can't compare them 1 for 1.
From what I recall, the rear seat was designed to suit passengers with thier hands cuffed behind thier back, and the rear seat could be easily removed for hosing down and cleaning of "occupant residue".
The car also came with built in security screen between front and back,
Front seats made to suit police wearing handgun, baton radio etc on thier belt,
Rifle and shotgun racks [every car should have these]

"Police pack" electronics / computer and communications systems and screens,
Uprated suspension/ brakes/ engine,
All the police warning lights and spotlights and sirens.
IIRC, some had fire suppression systems built in - and even column shift was available to free up room on the centre console for more police stuff.
I wouldnt call all that "low end interior spec"- more like purpose built to do its job!
Its not exactly a Belmont sedan with a blue light bolted to the roof

stephen