IMO your tire ballooning is a little short. I've done quite a bit of speed testing with the Stampede Talon. My closest estimate, on the conservative side, is .5 at 60, also I use a little higher voltage, as it does tend to rise back up on a top speed run. So mine looked like this.
Differential Ratio: 1
Transmission Ratio: 2.727272727272727
Other Ratio: 1
Spur Tooth Count: 56
Pinion Tooth Count: 20
Total Voltage: 7.6
Motor KV: 3800
Tire Diameter (inches): 4.6
Tire Ballooning (inches): 0.5
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 2.8 : 1
Total Ratio: 7.63636 : 1
Tire Circumference (inches): 17.59 inches (446.86 mm)
Rollout: 2.30:1
Total Motor Speed: 28880 RPM
Vehicle Speed: 63.01 mph (101.21 km/h)
Effective KV Value: 3800


That's why it's great to verify speeds, though. It could be right in the middle, I could be low, or you could be high, it's just hard to tell. I've been way off, up and down, before.

I am honestly having a blast with the 4wd on 2s. Around the confines of the neighborhood, it seems to mesh quite nicely. But I'm getting ready to head to the park, with a 3s, and the temp gun, so we'll see how that works out.

You know, as you seem to be a little heavier handed with the throttle, I'd like to see your results with the 3800 on 3s, in the 4wd.