trans upgrade e maxx

Thanks, Ill check on the gearing for the wheels and tires. I hope after the upgraded diffs and idler gears we can play. Have any of you ever delt with the ultrmaxx trans. kit? From what I can find out, it was a great upgrade for the e maxx but is no longer in production is this true?

P.S. Dafni, Thanks for the regear info. I may have to have your help on that calculation thing lol. maybe you can give me the formula to get the write gear ratio? oh and my son does not let his handi cap slow him down lol. He finds away to do anything he wants. trust me lol (he is my hero)