they are called transponders but there are a few different type. make sure you get the right one . amb is most common . thats a amb type..model # will also vary. just some fyi make sure the turn radius is same both right and left thru steering endpoints. do the ole in a clear space turn tight...
you have a giant selection of 4wd 1/10 scale buggies. does the track or local hobby store carry parts that's going to be 1 of your main factors.. there's lC racing team Xray(my favorite) and a few others.. do you know how to set a rc up? weight .motor so on. along with what type of battery...