Barely out of 2nd gear going what...................... maybe 40-50 mph? This M4 did almost the same thing with no tree to hit, but same result when the rear got away from him. I mean, I know ish happens, but I drive my Nismo and SRT8 like bats out of hell and have made the rears swing a lot more than these cars and I've never had a problem getting them back under control, but one thing Davey did say is important, I never let off, I keep the tires planted and start correcting.
https://www.youtube.com/watch?v=miA5qj5ergM