Since you're going to have to import a mustang into France and pay major shipping fees. I would definitely buy a real SSP instead of a regular coupe. Buying a restored one will cost you more money up-front. But it may be cheaper in the long run. There are plenty of fox body parts around, but the shipping cost of nit-picky parts to France, could make it unfeasible. If you have bought parts from the US, you know what to expect.
Also there are a few restored SSP's around. But not all of them are 100% correct. Most of the time it's lack of information and sometimes just not caring. It really depends on your preference.
The '85 CHP Matt has for sale is not completely restored, but the police equipment is included. That is another thing that is a pain to find. You will have to put some time into it but it's good for the money.
http://www.specialservicemustang.net...read.php?t=901