Appliance pros had the part. Incredibly, we received it the next day. They sent a confirming e mail with general instructions on how to replace it. Worked like a charm!
Our's is a Bosch unit. The retaining brass nut in the center of the burner is an odd size-20 mm which I did not have among my many automotive metric tools.
The local Auto Zone though had a 20 mm socket. Once that was removed the procedure would have been a breeze except the retaining screw on the old igniter was frozen. Had to drill it out and replace it with a screw I had on hand. Then, the new igniter was a perfect fit taking only a minute.
Note: do not try a crescent wrench or adjustable wrench on the brass center nut or it will round it off unless it is not very tight. Mine was very tight.and only a socket would do to get it loose.
With regard to the time the project took? Should have been 5 minutes were it not for the need of a socket I did not have and the frozen screw I had to drill out.