Is there a big negative to driving around in overdrive much of the time? I like the little bit "sportier" response it gives but not at damaging something.

 

driving without the overdrive is like driving without the final gear. so it would be like driving in 3rd gear all the time, causing to use more gas...

 

If you are driving up a long mountain pass, then yes, you should keep the auto in 3rd gear.

As for the revs- it wont "hurt" anything, but you will get slightly lower gas mileage...

In my 5-speed xB, the difference between 4th and fifth is around 500 RPM going 60MPH

Im my old Corolla GTS, at 60 MPH, the revs are at 4k!!

Knowing Toyota's quality, it should be a issuse......

 

Shouldn't there be an "n't" on the end of that "should"

 

Yes,

Their should NOT be an issue!