are the pros a lot stronger then the standard? I know someone said they are the hardened ones.. Are the standards still strong? stronger then the UEs?

Both are hardened, actually. The "pros" simply have a lower gear ratio(requires a larger pinion for the same overall speed). :)

So the pros have the 4.3 to 1 ratio over the 3.31 to 1 ratio?

Exactly. :)

Yeah!

Nice feature.. :p