OK here are the gearing options. Looking for a top speed in second gear of around 120Kph (75mph)

OPTIONAL PINION SIZES
1st gear 15,16,17 I have the 16 installed
2nd gear 18,19,20 I have the 19 installed

OPTIONAL SPUR SIZES
1st gear 47,48,49 I have the 48 installed
2nd gear 44,45,46 I have the 45 installed

The ratio of the drivetrain is 2.27272727 (50 teeth on rear axle and 22 teeth on the transmission shaft)

Tyre diameter
I will be using foam tyres. I expect the average tyre diameter to be around
73mm (2.874 in)


Please feel free to offer advice on anything you may think is of importance.
I am particularly interested in hearing about motor,battery and speed controller options.
After running the particulars through http://www.scriptasylum.com/rc_speed/_top_speed.html
I may need correcting but I see 2 options using the 1512 size motors.

4s LiPo & Neu 1512 1.5 or
5s LiPo & Neu 1512 2d

Again please correct me if I'm not taking certain things into account.
Cheers Andrew