Tbh I think mucking around with the stock intake is a recipe for issues with fuel trims and throttle response. Just playing around with the inlet scoop on mine to make some sort of carbonio type effect ended up killing low rev response, which whilst not sexy is where we spend a fair bit of our driving time. Similarly, most open foam filters on drainpipes do similarly due to the Bernoulli effect killing the speed of gas flow. I would be inclined to just fit a panel filter and clear away some of the ribs inside the stock intake. You will find a better return on your time by bashing out the precat.