[Sil3nt611]

I think your main problem would be fitting the hitch receiver because of the rear bumper cover of the ST. That being said, just eyeballing a similar angle of each car for comparison, the receiver looks like it hangs low enough that it would clear the bumper cover. It probably just depends how well it clears the exhaust.

As for towing, no car is really rated for towing because people tend not to use sense sometimes so no one can sue Ford for a tow rating. Cars can tow, and I've seen a video of an Escort towing an Eclipse on a tow dolly. The Escort was turboed and the dolly had electric brakes, and obviously the guy didn't accelerate or brake fast or go too fast. Would I ever do it? No. But it can be done. A small trailer with extra wheels on it should be a pretty easy tow for the ST. The Turboed engine should have no trouble pulling it, and the brakes are pretty amazing to me so stopping shouldn't be an issue.

 

[Sil3nt611]

It's likely putting a hitch on a sports model car isn't a particularly popular idea... If you want it done you're pretty much going to have to be the guinea pig to see if the regular Fiesta one fits or mock up your own.