Does that thin have a wide band O2 attached to the ecu somehow? If so just log that and you will be able to see how the afr’s are without buying anything else.
So to get this straight you have a stand alone, but dont know how to tune it? I am missing something here. Also dont most stand alones have an adaption anyways that gets you in the ball park?
Either way man, no knowing your afr under boost/power, I am sure you dont know your timing either. Lean + boost + lots of timing = kablooooooie in no time. i dont care if its a Nissan, VW, motor cycle, sled… a motors a motor and they all blow up the same ways! be cafefull.
go get a laptop, slap it on the ecu and do some logs and post it up we can help, but we dont have anything to go off of right now.