I have a 00' GV. I was wondering how much of a power and mpg loss can I expect with running 31's?

i've just put some 30*9.5 cooper stt's on my 03 zr2 2dr(4cyl).  i noticed a little power loss cruising on the highway up hills, gas mileage is worse, how much i'm not sure but i'm at the pump a little more often. 

i only run 29's right now on my 2000 vitara,  but there big lugged and i did notice a difference in fuel consumption.. so for power loss its only really notice able on hills. but mine is also maunal tran.

I have an 01 GV and I'm running the equivelent of 30" tires, a little difference but no lack of power. I think you'll be fine with 31" as far as power is concerned but from what I hear the CV" have a tendancy to break with that much rotational mass. But like I said I'm running 30" and went off road and no problems. Bottom line, you'll be fine I plan to run 31" later this year after my lift.