Do you know that a CAI scheme of taking air near the ground is not the best variant with maximum air flow? The variant that I described above is much better and it can probably give you more cold air than a CAI from XERD (but i don't know exactly if it is located near the ground or in front of the car).
As i think, most people know that placing an exposed airfilter under the bonnet is just asking for the engine to take big breaths of hot air. To avoid that outcome, it's now common to fit a cold air intake - 'CAI' - and seal it to the airbox.
However, what's generally not realised is that if a positive pressure can be generated in the cold air intake, the engine will perform better again.
Actual on-road measurements that we made by Autospeed in Australia show that at speed, a good cold air intake can easily have sufficient air pressure within it to completely cancel the flow restriction of the aircleaner. So, even though the effect of ram air on performance isn't huge, there's a worthwhile gain that can be made.
But getting that pressure build-up in the duct requires that the mouth of the cold air intake be sited in an area of high pressure. And where's that, then?
As the car moves forward, air is deflected above, below and to each side of the car. Some of the air is deflected over the top of the bonnet, passing along the bonnet, flowing up the windscreen, along the roof, down the rear window and then leaving the car's body at the trailing edge of the boot. (To keep the flow attached to the body in the described manner, the car must have gentle changes of angle only - especially from the roof to the rear glass to the bootlid.)
Other air is deflected beneath the car, flowing along an engine under-tray and then getting mixed with the turbulent flows exiting the engine bay (the air going thorough the radiator has to get out somewhere!) and the other turbulence created by the exhaust and suspension, not to mention the spinning wheels.
There is not such a big difference between kone and flat High flow Air Filter - if you provide them with cold air - both will act quite well

(especially TRD - I have it and you can't compare it with K&N - TRD is much better

)
Of corse, cone filter can take more air - but you can modify your air box to put it inside, because with this construction you will avoid a lot of dust to be inducted into the engine.
1MZ-FE TRD S/C. 2 BLITZ NUR Spec mufflers. SPA Boost/Fuel + Revotec water/oil/volt gauges. BLITZ Powermeter ID III, Denso IK 22 Iridium, TRD brake lines, TRD rear sway bar, fuel pump upgrade