Curtis Sparks Ignition Key

Has anyone used the advance key from sparks? If so does it help and how?

I do use one, and I think it gives a little bit more punch to the motor, first thing I noticed was easier to rev..and better throttle response.
and it works by advancing your timing by 6 degrees. Its more timed closer to the xr400 motorcycle timing. its really worth the 15 bucks......and besides if you don't like again your out 15 bucks.