I can't speak from expierence, but the only con I can see is the extra stress you may be placing on the tranny?
Pros: quicker, bragging rights, sounds great
Manuals spit clutches.....autos slip to death.....
Course it is variable and can depend on many factors such as prior driving/towing habits, neglect, etc.
Fwiw, I have a friend who's a toyota tech....
While he was speaking to their support gurus about my trans possibly slipping, the higher ups told him that while unrelated.......
The TUNDRAS with no more than a supercharger installed are expected to have slipping transmissions.
Kinda crappy imho for the Tundy crowd, but Thats what I was told.
Anyhow.... One must keep in mind that the toyota reflash for the Tacoma's can be hit/miss it SEEMS. Some run richer than others, and this MAY cause some to see more of a drop in mpg.
Why did mine stay the same if I drive normally?
I dont know.
I can destroy a tank in no time if pushed.... But, I'm over all the scrubbing off rubber from my fender liners, exhaust, bumper, and so on.