i recently bought a hitec servo for my tmaxx and the srew that connects the servo saver and servo keeps coming out. im thinking about putting thread lock on it, is that a bad idea?

also, my dad has watched me play with my tmaxx and is think of getting a nitro truck or buggy, but he doesnt want to spend as much as i did. hes not going to race with it or anything like that, just drive. what is something reasonable that he could get?

thanks!