Depends....the teal gears will give you less acceleration/torque but greater top speed (good for long run drags and such) while the orange stock will give you a sort of in between torque and top speed. And if you get the gear set it'll come with a blue set of gears which will max out the torque of the engine but, as you guessed it, will lower the max top speed.
So in answer, yes the teal gears will get you more wheel RPM and thus a greater top speed. (but again keep in mind less torque) You could even use gears for the Bit Racers (considerably higher top speed gear ratios but a lot less torque) but I can't vouch too much for those as of yet since I don't have any within my possession. Though hopefully that will be remedied soon.
Anywho, sorry for the long windedness, hope this helps!