New Tires having second thoughts.. Thoughts?

Hi all, after installing my 5100's, I thought I might as well upgrade to a bigger tire for a better look. After much shopping, I decided upon some Black Rock Steel Rims ($97/rim) 17x9 (37.65lbs) and wrapped them in 35x12.5x17 Falken Wildpeak A/T's (74lbs). Total Deflated weight is 111.65LBS so call it 125LBS inflated vs 85LBS Stock. Thats an addition of 160LBS of rotating mass. Using a rough estimate of a 1:2 Ratio of Rotating mass to Static mass, thats an addition of 320LBS. How much of a hit am I taking in the Gas Milage Department (Yes I know if I want good gas milage get a prius) and strain on the truck itself. Im looking at going to an alloy wheel to drop some more weight and solve some balancing issues, say a procomp alloy that only weights 27LBS, (10.65LBS lighter per wheel) that drop the static weight to 240lbs. Am I better off going to an alloy wheel to save the weight or will it not be a noticeable difference?

Thanks and here are some wheel pics