There is definitely a big jump from stock to modified courses. The stock course you probably wouldn't have to shift out of 4hi. I think the only thing that might prevent a stock H3 from doing the modified course would be break over clearance. Apart from that shortcoming (which is actually very good for stock) I didn't see anything on that course an H3 couldn't do. The rock garden at the end would be fun but would take more spotting than the lifted modded Jeeps. Would love to see a bunch of stock Hummers running that course in front of everyone
Of course would have to see them in person, very hard to get a true feel for the obstacles in photos or videos. I am very impressed with the courses they do setup. I expected them to be much shorter, took a lot of work.