The worst:The Tire Pressure Sensor not working and causing the tire light, ABS light, and traction control light to come on. With these lights on the 4WD will not engage.
The best:Engine, once properly aspirated, is a towing beast. THe 4-wheel drive shift on the fly is also really handy.
The worst:Emissions control systems rob power, engine life, and are expensive to maintain for relatively little benefit. Consider a lifecycle analysis of the system before assuming it's a net benefit.
The best:All the options and I finally got it the way I want it
The worst:As soon as the warranty ran out on the emissions, the filter plugged up, and of course, when the powertrain warranty ran out. The transmission started acting up.