go back and ask for the tech's car keys. Hammer the car until you feel better. Then find a new place.
oil change is pretty simple, a couple of basic tools, jack and stand. You can do it in few minutes. Even if you completely F it up, it's no more than hour.
if you're really concerned about hooning, tell them no test drive and watch them while they do the work. Or take the opportunity to do other work while its in the air.