It's not a replica, the K&N panel filters give improved air flow & better/quicker throttle response whilst retaining the original airbox....
The advantage a full induction kit has is usually the added benefit of an unrestricted cold air feed taken from the front of the car, (this can also have a ramair effect at speed), which will give added BHP throughout the rev range....Easily recognised because the cone filter is sealed within the induction pipework....
Cone filters will produce more intake noise than both the above, but would probably not match either for performance, (down to sucking in air already heated by the radiator & engine), this is especially noticeable in slow moving traffic where the under bonnet temperature is at its highest.....Easily recognised because you can plainly see the cone filter....
So, in order of performance;
1, Cone filter
2, Panel filter inside stock filter box
3, Full Induction kit