swamp lite tire size

I just bought a 420 rancher IRS DCT EPS and i’m looking at swamp lite tires my cousin has a 2013 with 26x9x12 on front and 26x11x12 on the rear. we put the side by side and his is smaller than my 2015 and I have stock tires. I think with mine being bigger the 26’s will look small. so I was thinking 27’s. what do you guys think. will it take away power or what?