AMA is just US stuff. WSBK (World Superbike) is 1000cc machines loosely based on the stock machines, I'm honestly not 100% on what components they share and what they don't. MotoGP currently uses 800cc "prototype" machines, which basically equates to anything goes type bikes. To my (limited) knowledge the WSBK bikes generally make more power, but the MotoGP bikes handle better and tend to lap a little faster. I think most would agree MotoGP is considered to be the best of the best, and WSBK would be the next step below it. I tend to like the riders "personalities" in MotoGP a bit more, I think they're able to be more of themselves than you sometimes see in other series'. WSBK can be seen on SPEED at various times, they normally run 2 races, and you can also catch a Supersport class as well, which run 600cc machines.
If I'm wrong on any of this please feel free to correct me, anyone.
2012 Kawasaki ZX-6R-Black
Clear Alternatives Tail Light
2005 Honda F4i-Red
2003 Yamaha Zuma-Fairy Silver
TPT 70cc Kit, Leo Vince ZX Exhaust, Malossi Delta Clutch, Scott's Damper Sticker