Just out of curiosity I removed the rear drive shafts going to the wheel on my Tamiya df03ra and ran it on the rally track that I set up in the backyard.

The car is much to light in the front (which was clearly visible right from the start) for making it a serious front wheel drive contender. I did not have the chance to run the front wheel drive configuration on tarmac, things might look different there.

One of the positive aspects of having the Subaru in front wheel drive was the noticeable amount of understeer in tight corners, which I was able to maneuver with more precision under high speed as compared to the all wheel drive configuration.

Below are the track times of the day, I alternated between all wheel drive and front wheel drive to get representative results that takes track wear and tear over the duration of a session into consideration.

All Wheel Drive
Fastest Lap | Average Lap | Total time 5 Laps
12.970 | 16.549 | 1.23
13.248 | 16.519 | 1.23
13.960 | 16.490 | 1.21
13.779 | 17.597 | 1.29
13.649 | 17.780 | 1.26
12.928 | 16.617 | 1.24
13.422 | 16.952 | 1.24 Averages

Front Wheel Drive
13.329 | 15.960 | 1.22
14.681 | 32.640 | 2.44
14.350 | 19.130 | 1.35
15.462 | 25.837 | 2.10
16.313 | 23.255 | 1.57
14.430 | 21.358 | 1.47
15.352 | 19.948 | 1.40
14.845 | 22.590 | 1.65 Averages

Conclusion: The front wheel drive configuration was roughly 1.4 seconds of the pace of the all wheel drive config. The average and total lap time numbers are not representative due to the fact that the vehicle got stuck in almost every 5 lap heat.  I will run the car in rear wheel drive configuration as soon as time and conditions allow.

The difference of 1.4 seconds equals to an average speed difference of 10.6km/h with all wheel drive and 9.6km/h for the front wheel drive car.

During a 5 lap race on a 39.6 meter long track the difference in speed accounts for a 7.1 seconds difference at the finish line.

See this post on how to calculate average speeds of a moving objec