Yeah, this little engine puts out some major umph! I don't know why people would want to replace it with a bigger one..
I did do some research on some tires and wheels. I used to have some Tamiya vehicles years ago and the wheel/rim/nut setup is the same on these. They both used a hub with a pin crossways in the axle. I will attempt to use some tamiya hubs and some 1/10 slicks on my tremor.
I love it!