I assume the stage 2 Web Cam is the 694 grind and the stage 3 is the 290? If so, per Web Cams website both require hardwelded rockers and valve springs. Even Web's bottom of the line cam for the 700XX recomends the rockers.
I know a bunch of people who run the Hot cams in their 450R's, never heard of any problems with them. No testing to prove it, but I would think the Web cam would make a little more power then a Hot cam. Web also regrinds a stock cam, hence the reason for the core charge, while Hot cam is an all new cam.
If you are trying to get every bit of horsepower you can, I would go with the Web cam. If you are just looking for a good boost in power, go with Hot cam. Depends on your budget also. By the time you buy all the recomended items, the Web cam is going to be alot more expensive.
Doug