Will all due respect;
I wouldnt be surprised if your cheap renegade mods cost you more in the end then your initial savings! Let me explain.
You're running your car with poor quality fuel, a faulty O2 sensor, a custom made intake and complain about getting bad MPGs. A lot of people here tried to help and all you did was arguing. Good to see you're hearing them now and hope you realize that those savings can results in huuuuuge losses.
You pay twice the price of gas; because you waste a lot. You're getting dirty injectors because you're running rich as a sheik and on the top of it; will those mods cause premature usage of your components? I hope not for you! But nobody know at this moment; not even you. Stop trying to convince yourself.
I'm not here to try to tell you what to do; its your car. But this is not my first modded car. I did that kind of mods on my old Celicas and Civics because I knew that the mods werent worth the investment, and that I was ready to accept that this could cause severe permanent damage that will make the car not worth repairing afterwards. I had my share of issues and i've learned the hard way; trust me. You dont do this on a car you want to keep; especially a bimmer. I wont get burned twice. A wise man said: You gotta pay to play!
I just hope you're conscious about this and know this car will get old FAST and that there's a 50/50 percent chances that your engine will most likely fail in the upcoming years.
So that being said, I agree, you got balls, but I just hope it doesnt backfire in your wallet.