An intake is not a requirement for big turbo...sure it can help suck in more air and wont hurt but its not a necessity, your green filter would be fine to start. Turbo first then spend later on an intake. You wont hit 400whp on just that turbo alone though, your stock fuel system will max out around 350whp. You will need to spend on aux fuel and/or watermeth and tune for it to see 400whp.I'm seriously considering going big turbo in the next year... if I can swing the cost. I've looked the requirements and the only thing I haven't done is an intake. My dream would be to get the CP-E Atmosphere kit but at over $4k, it's going to stay a dream. I'm currently leaning towards the ATP GTX2867R Gen 2 turbo since it's currently about $2200. Still expensive but a lot better than $4k. From what I understand, it's the most commonly used big turbo for the 2.0 Ecoboost motor and it is a direct swap. Making 400+ whp in an ST would be amazing. Thoughts?