I think Sanders in top shape would be a very good challenge for just about anyone. I wouldn't have even counted him out against Lennox Lewis. Obviously I strongly favor Lewis but I could see Sanders catching him early I'd consider Sanders a threat against pretty well anyone early in a fight. He is amongst the better punchers there have been in the heavyweight division his straight left was a very dangerous punch. If he could've brought that heat throughout the fight he'd likely have had the stuff to capture a world title. One fault of Sanders though is that he to was open to be knocked out.... I would've liked to see him and Tyson fight in the late 90's or early 2000's.
my answers above, prime sanders wins, Wlad's sanders get outgassed and outpointed. (possible ko loss due to lack of condition).
We're talking prime Corrie and prime Billups. The knockout obviously occurred because Corrie was still green.