Seems a bit harsh. Sounds like they're guilty without given the chance to prove innocence. As you say, there are lots of factory cars that can achieve the same things these tuned cars can do.
If they want to ban something, it should be the mufflers they're installing; quite annoying. This goes the same for the straight pipes on motorcycles as well.
Panny TC-P60GT50, Bell 9242, Yamaha RX-V730, Paradigm Cinema 70, Harmony One, HTPC