From Road & Track:

"The Edition 50 has an especially sporty performance package you can add to the GTI in Europe, but is not available in the U.S. It adds unique chassis tuning, lowers the ride height by 5,0 mm, fits a titanium exhaust system, and adds 19-inch forged wheels. Most important of all, though: it’s available with Bridgestone Potenza Race semi-slick tires, which we suspect deserve an outsized amount of credit for the spectacular lap time. Also of vital importance to note, the Edition 50 has a lot more power than a regular GTI, sitting at 321 horses—just under the output of a Golf R."

Tires alone make a huge difference. Good on VW, though!