go to loretta's, ponca, world mini's, look at the top 20. There are about 5 Polini's and KTM's there and about 15 Cobra's. Polini's supposedly have the power advantage with about 1-2 hp up over KTM and Cobra but I think its creative calculation there. They are all pretty evenly matched. Hill won the 4-6 stock class on his Polini but that kid would have won on a 5hp briggs minibike. The next few were Cobra's. KTM was almost non-existent in the top. In the 7-8 Class pretty much the same thing except a few more Polini's. If your kid will race 7-8 class wait and get a 2003. KTM and Cobra will have 12" front wheels and Most likely Polini too but I haven't seen anything official from them.
Jason...and Yes we do ride cobra.