Those look cool...

IST is a division of IXO Models, all Eastern European type stuff, really nice

M4 is an Italian company, they have two Police Alfas which are super

Progetto K I am not sure where they are from, I used to have some of their cars, kind of mid range diecast in my opinion, but unusual stuff

I have never heard of the other companies offered, but the cars look cool.

Jeff, a lot of the cars have been around a while, so its great that they appear as police vehicles also.
There were a lot of IXO cars released in a "taxi's of the world" series, and they were a fraction of the cost of the initial IXO release.
A lot of these series come up on spain ebay, they have done a series on vans, police, rally, taxi cabs etc.

Location: London UK

Here is a dodge dart spanish police
150291080081

And in white
160279667718

And a chevy nova
310080902284

Location: London UK

Progetto K is a long-standing Italian diecast company that makes only Italian cars, but has many police cars in its range, mostly older cars. They are good quality but unfortunately their markings are decals rather than tampo or other printing directly on the model. Since many of the Italian markings, especially the white stripes, cross door handles and other protrusions, the decals sometimes have air bubbles or otherwise can be fragile. The Edison Italian police cars in some of the auctions are made for a company called deAgostini that began a series of over 60 Italian Carabinieri models in 2006, then also started a series of about the same number of Italian State Police (Polizia) models. I have several of each series and they are well made, a bit above Hongwell in quality. These were subscription series that came with magazines, like the Hongwell international police series a few years ago, Norev's "Police and Gendarmerie" series and Altaya's Spanish law enforcement series that the Dodge Dart comes from. (Altaya, as Pete mentioned, is related to IXO.) Abrex is a Czech company that makes diecast models of only Skoda cars. They have 9 or 10 police models in 1:43rd scale, all of which carry similar State Police (Policie) markings except the yellow and white Commie-era Skoda 120 in one of the auctions and two versions of a Prague municipal police car. These are high quality models about equal to IXO, in my opinion.

Location: Woodbridge, VA

Abrex models are made by hongwell.

Location: UK