The mini-mules have a wider track than the production Matiz and the front end modifications speak for themselves. All four cars were sighted on I-70 near Denver, Colorado, probably either on their way to or from Pikes Peak. Pikes Peak is commonly used by manufacturers for high intensity brake testing as well as general high altitude performance evaluation. The fact that the car is being tested in the U.S. shouldn't be taken as confirmation that the car will be sold here. It's common practice for cars that are only sold overseas to be tested here, especially at extreme locations like Pikes Peak and Death Valley.
[Sources: Reader Rob and LeftLaneNews]