Ok so the only real competitors out there to Pac are SM and FM. I no longer think JMM has a chance, Pac is just to big for him now. Of Mosley and Mayweather I think Shane has a better chance. He has an iron chin, 1 punch power, great speed and stamina, and experience. Floyd has a very good jab and head movement that would trouble Manny but I dont think he has enough power to keep Manny off of him, sp Manny would chase him down all night and potentially catch him, Pac would be much more cautious against Shane.
Also, remember, Pac's next fight will be his last because he is going to run for congress. So he will only be able to fight 1 of the 2
mayweather. Mosley is getting old. He is also easier to hit and pac likes guys that are open. He doesnt like counter punchers
PBF. Shane's footwork is not good enough to stay with Pac IMO and he's easy to hit. He's way too flatfooted and Pac will be in and out on him all night not to mention he doesn't have a good jab. Pac won't hurt Shane but he would make him look bad.
Mosley would get something similar to what Cotto got if he fought Pac. Maybe slightly more competitive.