Welcome from Oregon! :smile
What
@mikey said, long version..
1) Do performance chips actually add 30+ horsepower and 8+ mpg?
IMHO, not an expert. Things that add HP don't usually increase mpg. I'd buy one if it really existed. Superchargers, turbos (not for the FJ), cams, compression ratio, exhaust... Generally all the above working together makes HP. How crazy you go with them affects drivability... Unless you are going to be a desert racer, you don't need to get crazy. You need low end torque for most of what we do...
[/COLOR]2) Is it viable to get a winch installed in a stock bumper?
There winch mounts that are installed inside the stock bumper. US OFFROAD makes one, there are others.
3) Realistically what should my mpg be?
No answer for that one. As I added accessories, suspension, bumpers, bigger tires, how heavy your foot is … on and on, my fuel mileage went down. Started around 18 and I'm down to 15-16 now. I don't have a heavy foot. Combined mileage, to the woods, off road and back home :smile
This is what the government thinks:
https://www.fueleconomy.gov/feg/Pow...&make=Toyota&model=FJ Cruiser 4WD&srchtyp=ymm
Only if your FJ is Blue I guess :grin