It reads air intake temp, coolant temp, rpm, pipe temp so on to decide what fuel to give. PCV just goes in between computer and the injector and most maps only change Full throttle fuel. So its doing nothing unless you got the throttle to the bars. And it can't change things like if its warm out the ECU will add more fuel, pull timing, PCV doesn't do anything while the ECU is making changes that make it run worse. You need bullydog to change these complex maps. Like mentioned there are like 30 different ones. Really not something you want to change trail side you need to collect a lot of data and look at the logs and go by that to make changes
Yes you get a pipe with extra bung for the sensor and it plugs into a box that converts it to digital that plugs into the bullydog. So AFR is displayed on there and you can data log it. graph it with other info RPM, throttle, DET, Pipe temp, so on
No you have to reflash the ECU. Its pretty easy though and can be done on the trail plug the power cord in to your battery and flash the ecu.