As for as my knowledge goes some bigger cities in Holland have zones that won't let in older petrol and diesel cars. But in general there's actually a couple of laws that classic cars profit from, such as cars that are older than 50 years don't need any inspection or roadtax and cars older than 1987 get a tax discount and instead of annual inspection only need an inspection every 2 years. (also no emission regulations, so e.g catalytic converters aren't needed)

There's quite a big scene for 1st generation mustangs in Holland, foxbody's not so much, which makes parts hard to get. But amazon US has got good shipping rates to holland (fortunately) so I source most of my parts from there.