gear up kits?

on my nrg lc i got a stage6 streetrace 70cc, 70cc cph highmass crankshaft ,polini reed petals, malossi variator(6 gram rollers) and belt ,17.5mm carb with a 70mj on standard airbox with leo vince zx
i need to know if a gear up kit makes adiffrence and what one to get primary or secondary and witch ratios as i want a higher top speed on a flat as get bout 60mph at moment an looking for 70mph on flat but i need aceleration still as live round an estate
(loves embarasing teenagers that say they do 65 with just sport pipe and want a race lol)
what are the benefits fitting a 21mm carb and open air filter?
your help is apriciated thanks