question

When I shift gears, how high should I be getting the RPMS up to before I shift? For best gas mileage.

between 2000 and 3000 rpm's

I always shift my 96' Jetta GLS 2.0 somewhere between 2500 and 3000 RPM's... However, shifting is a matter of Acceleration vs. Lower Fuel Consumption. The lower the RPMs you shift the better fuel mileage your going to get, but shifting too low could also be bad on the engine.

I would stick somewhere between 2000 and 3000 RPM's.

Someone once told me, 10-19 for 1st, 20-29 for second, 30-39 for third, 40-45 for fourth and anything over 45 MPH to be in fifth, that is for optimal mileage... but I call it granny shifting. :)

Id go with 3-4k RPMs because if you shift too low you dont have enough power/RPMs in the next gear hence causing you to hit the gas harder and use more gas...