the .46 motor will only have alot of torque, it wouldnt have alot of top speed. If you want to up grade i reccomend the sh.28 pro, axial .32, those seems to be the best for power, speed, price, and overall fun. The .32 has a bit more torque. this is what i have heard not from personal experience. I would probably get the .32! cant wait til i get my savage! then i can get that engine!! should be mean as :) I cant believe that these powerful engines are so cheap!! theres alot of them coming out.