Too Funny! These guys did it all: "high" marking, sidehilling, jumps, donuts. ditchbanging.
Saw this a couple of years back. Pretty sure that at least some of it was filmed at one of the I-29 overpasses (aka Mount I-29) in North Dakota.
Thinking they had to be one lungers if they were stock but either way it looks like they were generating some pretty good trackspeed - it's all about trackspeed.