Please help me beat a dead horse.....

We made our trip to Ala. Saturday, about 350 miles round trip. The new tires definitely helped with the ''wandering'',, I THINK I perceive a small tad--- she says, ''No''....We both agree that the car rides better, handles lots better, and are quiet. [ she drove the last 50 miles home, some interstate and some 2-lane ''country'' roads] It appears that I have taken a 4 mpg hit so far, perhaps it will improve after 1,000--2,000 miles--- but--- I can live with that. However, I filled up at ''Sam's Club'' in Meridian, Ms on the way home----$3.07 per gallon, cheapest gasoline for me in a while....
My next project will be to install a Cusco STB and center brace,, through fooling with it then.