Finding an E30 M3 isn’t particularly hard.
Unlike contemporaries such as the Audi Quattro, locating a good example on any given day of the week is easy. eBay has no less than seven for sale at the time of writing, all in generally good shape. Specialists such as Enthusiast Auto Group (EAG) have the same number, none of which would be unwelcome at a high-brow show. Since BMW brought over 5,000 of these homologation specials to the U.S. market, you don’t need to search long and hard to find exactly the E30 M3 you want.
Paying for it is another matter entirely.