Help with gearing please?

[jasjeet]

Just bought an Xray T2 from a user here, but need some help with the gearing.

I have a Reedy 11T Modified Brushed Motor, the Spur is 84T, what kind of FDR should i aim for? I think the internal drive ratio is 2.3 or 1.9.

Going to be using the car for general car park blasts.

I have worked out the current FDR of my TT01 with this motor is 6.85, should i aim for the same FDR or closer to 7-7.5?