I try searching however, I can not find a definite answer.

I am wondering, if the AEM EMS with UEGO build in... is the same as AEM EMS without build in plus a seperate UEGO controller?

because, I heard AEM EMS with UEGO build in will compensate A/F ratio according to the UEGO reading. Does AEM EMS without UEGO build in w/controller do the same thing?

 

The EMS w/o UEGO will not compensate AFRs based on UEGO reading.

Note however, some tuners will not use the UEGO feature anyway. So check with your tuner to see if you need to spend the extra cash for the UEGO.

 

My son had a Nissan 200SX with an SR20DET and some other modifications and he was able to obtain a near perfect tune on the street with the EMS/UEGO combination. It took some time but it never saw a dyno but was able to to run mid 12s in a car that was set up more for drifting and never got better than a 2.1 60' time.

Rob had the built-in uego with a separate gauge for the wideband reading but he is pretty sure the combination you mention will do the same thing (self-tuning).

Just bare in mind the car won't tune itself. You will have to get it in the ballpark but a canned set of maps from AEM may do the trick, depending on your other modifications.