Should I have base plates professionally installed?

The mechanic is going to do what you or anyone would, and that is take out the instructions and read them. As long as the work is guaranteed, I would go with the lowest bidder. I did all of mine and they are pretty easy. Taking of the entire front clip of my Grand is something a body shop may be used to so they may be a little more adept at the process thus doing it faster. Other than that, it is a step by step thing anyone with a little mechanical inclination can take care of.