While the Dark Horse is said to effectively replace the S550's

Mach 1 variant, which itself took over in principle from the

previous GT350 as the sweet spot of the track-biased naturally aspirated Mustang

experience, the Dark Horse's price would suggest that a

 a potential GT500 would be ridiculously priced.

We only say so because a fully loaded S650 Dark Horse is costlier than an S550 GT500.