Ford Capri!!!!
Yes, it was the Ford Capri (second version as there had been an earlier version with the front end from the Ford Classic) that spawned the 'letters' fad.
While it had always been possible to get a GT version of some cars, Ford introduced the 'custom pack' concept so you could have the 'X' pack, the 'L' pack or the 'R' pack........................or
you guessed it, all three and buy a Capri GT XLR
complete with black bonnet
and the rest, as they say, is why we all drive around in CSRs, GSis and so on.
GT, of course, will always remain acceptable, standing for Gran Tourismo