Had a blast running modified.
However, the ESC gets pretty darn hot like 65 degrees Celsius hot. I'll let your figure out the temperature in Fahrenheit.
Jumping from 1/12th 21.5 2s to 3.5 1s isn't soooo bad. It's probably the most fun I've had in awhile. Having all that power at your disposal, wow. Love it. Just pull the trigger and let it rocket down the straight. You will need to adjust your driving style to accommodate for the extra power, such as smoother on/off throttle and turn in timing points on the track. By far the most important thing for me is being comfortable with your cars setup. I can see it being nerve racking if you don't know how the car will react in the next corner.
First round of practice...
After settling in on a decent tire setup I focused on tire diameters sizes. First I tried a large diameter of 42 mm and 42.5 mm. I found the larger sized tires difficult to cut in and follow through the corner. Though, easy to drive, I wasn't able to drive the car hard or tight into the corners. The sidewall being too large caused the rear to be locked in.
Next round of practice...
I decided to try out the complete opposite with 39.8 and 40.5 mm tires. I found the car was really fast and really quick in the corners. However, the foam was too thin and the cars rear end started to break loose after 3 minutes. Though, the tires were old, the lack of a sidewall made it difficult to maintain stability in the corners.
I decided to run 41 mm and 41.5 mm and that was the hot ticket. The car carried corner speed and maintained a good amount of traction in the corners for a 8 minute race.