same ratio dfferent gears

Generally speaking even if both ratios are say 3:1 a lower toothed pinion will have better braking so 30:10 will have better braking than 33:11 but on the other hand they will both have the same top end.

One reason for having the higher pinion would be to reduce the braking and there fore reduce chatter. You could also go the other way and say lower pinion will give you better breaking and therefore stop quickest .

Yes rick that maybe but on a slot track the top speed so long as its the same ratios are generally speaking going to be virtually the same whereas the difference between a 9 and 11 tooth pinion braking is a big difference

Life's not all just maths , this is from experience of the way cars go

Well a 6 tooth 5 mm pinion will obviously weigh less than a 13 tooth 8mm do it may well have more acceleration ...

Exactly and thats coming from an apprentice electrical/mechanical engineer. These are toy cars after all , and yes hollow axles do make a difference