[lincpimp]

Keep in mind the diff ratio is 44/14. So with the 51t spur and a 25t pinion you get:

Differential Ratio: 3.142857142857143
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 51
Pinion Tooth Count: 25
Tire Diameter (inches): 4
Rollout: 1.96


Std buggy diff ratio, 46t spur and 35t pinion:

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 46
Pinion Tooth Count: 25
Tire Diameter (inches): 4
Rollout: 2.06


Std buggy diff ratio, 43t spur and 25t pinion:

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 43
Pinion Tooth Count: 25
Tire Diameter (inches): 4
Rollout: 2.21

So not a huge difference to a 46/25. I would not worry.