Here's the latest setup:
I now have a hitec servo (green arrow) for braking because the stock Traxxas one was the reverse of what I needed. I just hunted around the ones I had until I found one that turned in the right direction. Can't put the radio throttle in reverse because of the ESC.
There are also two 5V fans (green circles) spliced together and plugged into channel 3 of the receiver. One is pointed at the speed controller and the other is pointed at the motor. A bit of running in my back yard and a few speed runs on the street never got either the speed control or the motor very hot. The maximum I read for the speed controller was 118F and the maximum for the motor was 113F. These safe temps in what was about 85F ambient today lead me to believe I could move at least two teeth with the pinion and possibly some with the spur.
Either way, here's the awaited speed results.
The highest I could get it in my back yard was 21MPH even.
On my street I was able to let the motor wind as far as it would go and it pushed the Jato to 36.8MPH.
Considering I have room to play with gearing due to the good temps, I'm sure it could reach the speeds of a nitro even with just the 2s lipo. Next, I'm thinking of putting my 3s pack in and seeing what it will do :)
36.8 is faster than I will drive on any track and clearly faster than I can use in my yard, so I doubt I'll do much more experimenting with the gearing. I appear to have hit my mark on the first try :)