If there were two things that I wish I could try before I bought them, it would be tires and mufflers. Hopefully this can provide some guidance if you are looking to invest in bigger tires soon.
This is a v6 3.3L, and it came stock with 15" wheels and 30" tires.
I had 31" tires on my previous Frontier, so I wanted to try out something a little taller and went with 16x8" Mickey Thompsons (-12 offset), and Thunderer Trac Grip M/T R408 285/75R16 (33"x12.5").
The Frontier lug spacing is 6x5.5 or 139.7 and if you need to buy thinner lug nuts to like I had to, to fit in these Mickey Thompsons, you're looking for M12x1.25 thread nuts.
Currently averaging 16mpg.