That's why the 288 GTO is so cool. The F40 was the final stage of the 288 GTO Evoluzione program. The original 288 GTO had no ground effects, the Evoluzione program was the racing version with ground effects and more power (about 600 hp) that was to be part of the FIA Group B competition before it was cut short after a bunch of accidents.
The original street version is my fav F-car because it has the wacky crazy engine from the F40, albeit with not quite as much power, is reasonably sort of liveable, and only weighs 2500 lbs. Oh and there were less than 400 made. Good examples command about 300 grand at auction.
Without the 288 GTO, there would be no F40, F50, or Enzo.