There is a difference in top speed between 1 and 2 speed transmission. It can be upgraded but its kind of a pain. Some people have the 2 speed transmission and can't get it to shift. Just stick with the one speed for awhile until you get used to RC nitro, then you might as well upgrade to another brand of vehicle. The plastic parts will break if you smash into something like curbs and trees. Try to avoid hittting stuff and you shouldn't have a problem. Enjoy!