These are both incorrectly written. Why? Because first person subject pronoun is 'I' - not 'i'. The capitalisation of this word is not optional. It is not a question of choice or relative formality - 'i' is simply wrong. And to answer your question, both forms of the verb are acceptable. The subjunctive 'were' is, strictly speaking, more correct, but the 'was' form is also acceptable. As an examiner, I wouldn't mark you down for writing or saying 'If I was..'. But I might mark you down if your essays were full of 'i' instead of 'I'.

If i were you is grammatically correct. but i'm sure the two are all being used nowadays.

I think they will say it's the first option because this situation is impossible. I think that "if a was" is used in sentences like this one, "If I was interested in German culture, I would study the German language" because this is possible, whereas, "If I were a girl, I would wear a bra" because this is impossible for me to be a girl. Just like an example. That's why I think that in your case the first option would be correct because you can't be "me".

In my opinion, both are correct. However, the first option is considered more proper as it is in subjunctive form. But, it's not used that frequently nowadays. Most people would say "if I was you," instead of "if I were you."