Take the K+N back, they are illegal these days for a few reasons, the main one being they cover the AFM in oil causing them to miscalculate the airflow.
Pod filters are crap, they suck hot air from the engine bay unless they are in a perfectly designed and sealed CAI, It would cost you plenty of coin to even get close to matching the efficiency of the stock airbox.
I have seen the standard sized Nissan panel and airbox flow 500kw so the intake is not your problem. ^^ Listen to Bob, tyres, suspension and brakes would actually make you faster and safer.