I use an impact gun on mine all the time. After all these are 1 ton axles :. Being a professional service person, nothing ticks me off more than someone coming up to me to instruct me on how to do my job correctly. That is of course that it's not my boss. I'd let them do their thing and then check the results afterwards and deturmine if you like their work enough to go back next time. But honestly, if you look at those hubs on our axles, a few extra Ftlbs isn't going to do any harm. You just might not get them off on the side of the road with the lug wrench provided in the tool case.