Have a badlands 2.7 2door on 37 ( recaliberated for tires) and a k&n filter nothing more .19.8 to 21,9. Depending on what cheap gas i use. Dropped my 4 door badlands ( wifes mall crawler) to 30.'s and it gets 22.1 to 24.5 with a K&N air filter..
My wife has a 4 door 2.3.and I have a 2 door 2.7.The difference is night and day..The 4 wasnt a bad .But my wife hated the performace so much she traded it in for a 4 door badlands 2.7..
The problem I have with 4a is the time it takes send power to the front wheels .I find the bronco rear wheels lose traction alot .So I use 4 h in ice and snow!