Rene kit gives a really brilliant intake roar.
K&N don't do an airbox mod, it's just a replacement filter, I think you mean the Evo kit.
I have the Evo airbox mod (couldn't get a rene kit at the time)
Either kit flows more air and you can get more power if you remap the injection, probably means a PCIII as I think it's outside the range of the Axone.
There is a guy on RSVZone who makes a Rene clone kit that's got pretty good feedback you might try there.