It's been deemed too "loud."
Ferraris are extremely loud, fast and expensive, but the automaker has an entire lineup for wealthy enthusiasts that are interested in destroying track days. The Ferrari Enzo FXX is one of the supercars that was engineered to do one thing extremely well: demolish a track. The Enzo ZXX Edo Competition in the video below is one of the few track-legal variants in the world that has been tuned to produce 950 hp and can hit 245 mph. It's a monstrous supercar that happens to be street-legal, but it's too loud to be used at Spa Francorchamps.
The supercar registered at 142 decibels, which was over the limit for the track, thus making this supercar an expensive paperweight.