[Starchy]

If you are asking if getting a wideband is necessary then yes. I just purchased an aem e85 wideband and i need to get a wideband bung welded onto my zzp dp, and im guessing if your dp is stock then you will have to do the same unless you bought the dp from zzp and have an extra 02 for wideband installed.
I might be a little confused by your question... but how would you be able to tell your air to fuel without installed a wideband?

 

[Starchy]

BTW A/F gauges are expensive... there is no way around it if you want good readings