Just over a year after getting the Volt914 running, I've spent some time thinking of "if I had to do it all over again...". First - choice of motors (AC vs. DC). I'm occasionally disappointed at the performance of the AC24 motor. So I played a "what-if" game - I found some power output curves of the original 1.8L engine in the 914, and plotted a curve of horsepower vs. speed (assuming that one would always shift to maximize horsepower). I added curves for the AC24 as well as the Advanced DC 9":
You can clearly see that the AC24 is lower performance than the original motor, not even taking the extra weight of the batteries into account. The ADC 9" is generally higher performance until you get to 60 MPH or so - probably even taking battery weight into account.
So, if performance is your desired goal - go with DC. I do believe the range of the AC option is greater - higher efficiency, lower HP in general, the option of regen braking. Given that I mostly commute with the volt914, I think I made the right choice.
The next "what-if" game involves batteries. I'm somewhat discouraged by the acid issues with the Zivan charger and floodies. So much so that I'm saving my pennies for an upgrade this summer. I'll either go with AGMs (and a new charger) or, optimistically, something exotic if the prices have dropped enough. Stay tuned.
Other than those considerations, though, I'm very happy I did this project.