The only way to really get more out of it would be to do the 2.5 conversion and put in a bigger engine such as a good .18 or one of the made for T-Maxx mid block engines like the Picco Maxx .26/JL Red Dot, RB TM523, OS .21TM, Sirio .27Max. The LRP .28 that was suggested would only work if you did a big block chassis conversion and would sherd the entire drive line before you could even get it broken in. As your Maxx sits right now it will be hard to get a ton more out of it with out dropping some coin.