I got a 21 kw diesel Isuzu 4 cyl 1800 rpm from Valdosta GA
About $11000 delivered
PDG was the outfit
I would go with doing my own, as I am a EE, but I am not a licensed electrical contractor, so working with the utility company to turn off and inject the switch isn’t an option, so if someone else has to do that part, might as well get them to do the whole job, and I really don’t have the time for it anyway. If I were off-grid, then I would easily get an Isuzu. Great machines.