So today I knocked the F1 car off a bench while I was cleaning up parts. Only broke a rear wheel off - survivable level A+.
So I grabbed a spare driveshaft and took advantage of having to rebuild the rear, to balance and true the driveshaft with a heat gun and a sanding block to eliminate the wheel wobble that comes from the tendency of the driveshafts to curve when cooling. I also drilled and inserted a 2mm set screw in the spur gear to fix it from moving (visible in photo). Helicopter guys call this a “Jesus” bolt.
The new smooth drive did wonders for the cars top speed and grip. It was raining this evening but I went out for a test run anyway - I continue to be amazed at the grip these NinjaFlex tires deliver in the wet when combined with the car’s inherited aerodynamic design. With a new top end speed and handling improved by the trued driveshaft one can begin to explore its natural affinity for high speed. Once you get going fast enough for the aerodynamics to kick in you can see the car hunker down and it actually becomes much better and easier to control going faster. It really becomes alive and finds its home going fast. (Nice!) Folks who have driven real F1 cars say one of the most difficult things to get acclimatized to when driving them is that you must drive them fast, they just don’t work well going slow, and this model inherits a little bit of that through its aerodynamics. You also get a reminder of how much the aero downforce is doing for you when you go over bumps and you lose the downforce when you become momentarily airborne, and it becomes squirrely again.
Even though it was wet (and the car kicked up impressive rooster tails through puddles) the new smooth back end and the aero kicking in (whee) let me be confident enough to open it up a little more than I have before and I finally explored the area above 50% throttle. To show you how much grip the tires and aero give, on one high speed run I opened up the throttle to about 75% - 80% percent on the neu-castle 1410 3800kv 4 pole motor - and discovered the next physical torque limit on plastic cars, I shredded the teeth on the spur gear (see attached photo) even though it was running on wet pavement in the rain. With a stripped pinion gear, the motor sounded quite fun free running (attached video).
So now there are two paths to going faster. Either determine just how much torque one can put on the teeth of the 100% infill plastic pinion, and fiddle with the torque limit curves on the motor controller to dial it back to an acceptable non-gear shredding level or… Option two is to use this nifty little combo my buddy Seb at Seb’s RC Shop cooked up for me when I asked him about it in the third attached photo, and then find out just how much torque the plastic spur gear can take… 
Addendum: So that metal 14 tooth gear is essentially the same as the stock plastic one. BTW just did the math, this works out to a 160 (159.7 but gimme the .3 because I used 12v for the nominal battery voltage) Kph real world theoretical top speed (53mm diameter tires, 3800kV motor on 3s pack, 40:14 gear ratio). I’ve only probably had it up to 50-60 Kph now. It is fast enough to chase real world cars down residential streets. Wonder if it can get anywhere near that theoretical top speed without a fancy aero underbody like Traxxas used for their high speed car…
