well, had my first race with the full mod. motor was very strong. during practice i could feel it spool up faster than the race prep, but it did seem just a tad smoother coming out the gate. then i had some glo issues. found that the silicone used in the crank had come loose!! cleaned out all the debris anda fter that the full mod was a rocket. it hit so hard and fast that i had trouble controlling it. hopefully i can get the motor taken care of soon so i can get it back for our first pro-series race in 2 weeks. overall i love the js engines.