Sounds like you stripped the threads out of the throttle body.... Instead of just messing with needles go to factory settings and change the high speed needle first only 1/8 turn at a time. Make sure you know if its to rich or to lean (it takes some experience to know how it sounds but look for smoke... lots of smoke means its rich and no smoke means its lean)

I do have a racing backround and I find the stock tires to be trash especially on track . Of corse any tire is a good tire for bashing though.