Typically its a price issue when you hear two "similar" companies - they have a "cheaper" brand that is basically the same product - kind of like their own generic - a prime example is rims - you can get the $300 ford rim for $125 from "Ford" they just brand it differently at the cheaper cost....quality is typically the same or close to it...
The answer to your question is I do not know. But companies do may two different gears sets for street and race. A street gears will be better in high mileage use and a race set will take more HP. Sometimes they use a different steel and they also harden them to a different Rockwell.