How much power loss?

Hey everyone. I just picked up a new 2010 access cab 4cyl 4x4 a couple weeks ago. Its got the plain steel wheels and dunlop grand trek 245/75/16 which is about a 30.5" tire on it. I want to add some nicer wheels and tires in the near future. I know the biggest size I can go up to without a lift is a 265/75/16 or about a 31.6" tire. After doing some searches on posts on here it seems like some with 4cyls say they lost alot of power, mpgs, and put alot of stress on their trucks going with that size tire. Others say they didnt notice too much of a difference. Just wanted to get some opinions on how much power/mpg/added strain you noticed by moving up a tire size or two.

Thanks

 

I would guess that most of the complaints are from people who have the 5 lug trucks. The 5 lug trucks are geared differently than the 4wd and prerunners, so lifting a 5 lug and putting on 31" tires really bogs it down since the stock tires were 26". You've got 30.5" stock and only going up by an inch, so I wouldn't think it would make too much difference.