I just found the video (googled for yellowbird and nurburgring) and he's not drifting in the showboating, maximum-opposite-lock-at-every-corner sense of the word. He certainly gets some lock on through a few corners, especially the ones where they bothered to use the external camera footage but he's not deliberately shredding the tyres. Even so, by the time he got past the karussel (about the 5min mark) the back tyres seemed awfully secondhand. It sounded like he wasn't leaning on the throttle anywhere nearly as hard as he was at the start of the lap and the transitions to sliding were a lot smoother so I'd say his tyres were getting distinctly greasy. Awesome driving though.