Motor temperature directly relates to your gearing.
FDR = (Spur Gear / Pinion Gear) x Internal Gear Ratio
If the FDR is too low or too high, your motor temperature will be very high and may burn out.
So you need to check the manufacturer's gearing recommendation.
For 4500kv motors, target FDR ~ 9.0 (buggy)
For 5500kv motors, target FDR ~ 10.0 (buggy)
For E-firestorm/Truggy, add 1.5 to above FDR is better.
DF03 is 4WD, so with exactly the same settings, it will be a little slower than a 2WD. since 4WD has more components and heavier. So typically 4WD can use a faster motor than 2WD. (2wd suggest 5500kv, 4wd suggest 6500kv)
It also depends on DF-03's internal ratio (IR).
Since FDR = (Spur / Pinion) x IR
Note: It also depends on the DT-03's plastic gears, whether it can withstand the heat. The heat may melt the gears together. so be careful of using a very fast motor!