Inferno ST-RR Gearing Question

Thanks for your answer Simplechamp
I have used the calculator you have provided and I have come up with these:

Differential Ratio: 4.3
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 50
Pinion Tooth Count: 10
Total Voltage: 22.2
Motor KV: 2200
Tire Diameter (inches): 5.8
Tire Ballooning (inches): 0
Motor Current Draw: 120
Motor Coil Resistance: 0.006
Spur/Pinion Ratio: 5 : 1
Total Ratio: 21.5 : 1
Tire Circumference (inches): 18.22 inches (462.82 mm)
Rollout: 0.85:1
Total Motor Speed: 47256 RPM
Vehicle Speed: 37.93 mph (60.92 km/h)
Effective KV Value: 2128.65
KT constant: 0.61 oz-in/A
Motor Torque: 0.38 ft-lbs
Final Torque: 8.26 ft-lbs
Final Power: 2664 watts (3.6 HP)

I am opting to use a 6S 30C and 5000mAh Lipo

I have noted that as I increase the pinion gear's T number and lower the Spur Gear's T I am getting higher theoritical end speeds. If I am correct to this then the torgue is lowering accordingly?
I am interesting in bashing and be a bit speedy on the field.
Is there a way to estimate the run time on a 6S battery with the aforementioned characteristics?
I am going to post in the project session soon enough for everyone to have a look and present their opinion.