With all the recent news about doping in cycling, I got to wondering: Anyone ever seen any reasonable estimates as to how much EPO, blood doping, or other methods would help one's VO2 max, lactate threshold, and other measures?

I'm assuming there aren't any experiments around on this, but just wondered what the payoff for a highly-trained athlete would be expected to be. We assume it's pretty big, but then again anything that gives one the slightest edge in a tight field might be worth it.

I know for the grand tours, using EPO just to keep your RBC count about normal over the course of the race would help toward the end.

Edit: I, uh, want to know for...a friend. Yeah, he's a Cat 5 and picked the wrong parents. Which totally isn't fair. So what's wrong with leveling the field a bit?