...the a/f automatically with the EMS, or do you still need to dyno tune. I was under the impression that it can be used by itself as a wideband UEGO monitor, but when hooked to the EMS, it would be able to self tune.

 

You can use it to auto tune. but I do not like using it as I can tune quicker using the the traditional methods. You can also use the uego with the aem to run in closed loop so the aem makes small adjustments based off of what it is seeing to get the correct afr due to changing weather conditions, altitude etc..