100 series tyre size bfg km 2

Hi all, I know this one has been asked many times, just seeing if there is any info on new bfg km 2 tires. I have a 2006 manual ifs cruiser. I have geolander a/ts 276/65/17 on at the monent. They came on car almost new. I have been on every surface except mud. I am worred about traction and after bfg km2 285/70/17. I have always had bfg mud. But 32s on a patrol. I have read I will loose fuel economy and power. Is this worth the extra 20 mm under diff? Are geo bad in mud for a a/t? Had thought if a 3inxh exhaust to make up power loss or just run a/t out. Or a second set . Prefer not to have second set. Any thoughts thank you.