A single cone filter already provides more airflow than the little 1.6 could possibly burn, adding a y to it and a second filter would do nothing but add costs and complexity where it is not needed. you would be far better off to look for further efficiencies in the exhaust and throttle body areas. also, more air and more exhaust flow, along with a bigger throttle body still leave you at an impass, as in order to use those you will need more fuel and a computer that knows how to use it.