Larger pinion = taller gearing = LESS acceleration...
If you think better acceleration will help improve your laptime
then you need to try a SMALLER pinion (lower gearing).
Make laptimes your best measure for gearing... go up or down
until your lap times stop getting better, that's the only yardstick.
Any 3000 will be more than enough runtime for a stocker.
It don't matter if your batteries come back half-full as long as
your car is lapping as fast as possible.
You can't do much to a stock motor, but you can change its
brushes & springs. These can make a little difference.
Keep your motor well-maintanined & lubricated always.
There's also always better batteries out there, ones with highest
voltage and lowest IR for the best punch. This can lower laptimes.
Think the 3300s are better cells than 3000s too; if 3300s are what
your competition are using then you might need to join the club.
Not for the runtime but for the other better specs.