cool i saw them on a site for sale too... but i don't have a big spread in my gears but if i do get that 4 to 6 teeth spread or more then ya...Here is an attachment of the FG Supply heavy duty 2 speed hub , note the reinforcment behind the pins and the pins are thicker in diameter than the stock unit on the right . This design should make it more durable for high output motors like you would use in drag racing.
i have not been able to test it yet after inputing the new spring. to see if it is shifting i will try today...