So far in Ford’s documentary series about the development of the 2016 Ford Focus RS, we’ve seen clay models, Ken Block, and crash test dummies all make meaningful contributions to the design of this 350 horsepower hot hatch. But the real brains behind this high performance machine are the dozens of Ford engineers from all over the world.

In the third installment of Focus RS: Rebirth of an Icon, we follow 30 of those engineers on an American road trip meant to test how the early prototypes fares in the real world. Unsurprisingly, things don’t go quite as well as planned.

For example one engineer complains that the route has Ford’s engineers spending too much time driving through small towns with low speed limits. However, the Focus RS does perform well at higher altitudes where thinner air can have a measurable impact on power. The engineers don’t all agree on what changes need to be made however, with some commenting that it should feel “sportier” or that the “choppiness” was “off the charts”. But that’s the whole point of these test drives, to get a feel for what’s good, what’s not so good, and then to figure out how to fix it.

Being prototype cars though, it was almost expected that mechanical problems could arise, and for a time one of the RS testers is sidelined by a funky noise at the rear. But with 30 top notch engineers on hand, the problem is sorted out in short order, and the cars are back to pacing through an idyllic American setting.

Now that the road tests are through, we wonder what’s next in this series. Track testing? More interesting engineering? Ken Block, again? Stay tuned to find out.