The new motor controller is installed and the road test has been successful!
I first put the car on jack stands and did extensive "driveway" testing. I ran through all of the gears numerous times, including reverse. I took it up to 55 mph on the speedometer and held it there for a while. I did numerous shut-downs and component inspections.
I was satisfied with the results so I took the car out on the street. I didn't push it too hard but I put on about a mile going to the corner and back several times, as I didn't want to have to push it too far if it failed again. On the final run, I quickly went through all the gears and got it up to 28mph before letting off.
Not wanting to spoil this long-awaited successful moment, I decided to call it a day at this point and parked the car. I then did a final check for excessive heat on the components and connections, which all looked good.
If you've read the posts leading up to this one, you have a sense of how much this success means to me at this point. Rather than chance ruining the moment, when I was finished checking everything I PUSHED the car the final 10 feet into the shop. LOL
More rigorous testing will follow. However, the weather is turning colder again and I have to return to work tomorrow, so I may savor this success for a week or so before I do any more driving :)