Cobra tuner question

First off I have read just about everything on the sticky thread about the cobra tuner. My question that is see different models, I see the auto tuner, stand alone, and stand alone with O2 sensor. For my budget the stand alone fits easy, the stand alone with O2 is slightly more and could make penny pinch but it's doable, and then you have the auto tuner which will not work with my budget. So the question is will I be ok with stand alone paired V&H big radius or should I go with the O2 version. The info for those two look about the same so I'm a but confused. I'm new to fuel injection so I don't wanna mess this up. If was carbs that would be a no brainier, jet kit.