Do you Tundra owners find the mileage to be in the 12 mpg range? That 5.7 is a big engine. I note their web site says 13 to 14 city slightly better on the highway. Most reliable truck out there right now.
On my 3rd new generation Tundra.
I get 14 to 16 MPG, 50% city, 50% highway, with a heavy foot.
I wouldn't pay thousands extra for a sticker and upgraded shocks and wheels, which are still mediocre stock equipment.
Buy a base model that has the trim, engine, features you want, and drop $3k on suspension, wheels and tires. You'll end up with an even better truck for less or similar cash. And if it bothers you, buy a TRD sticker on e-bay for $10 bucks.