I have to say that the Kayfun is quite old now in the scheme of things, and was designed during the days when low ohms, high wattage builds weren't so popular.
As standard, it is not particularly well suited to such builds, in my humble opinion.
There are people out there that can mod the airflow for you and indeed increase the size of the feed channels, you can even do these things yourself if you are confident with a Dremel.
I would suggest that for anyone looking to do high wattage, low ohm vaping on a Kayfun style device, that doesn't feel like modifying their Kayfun, should probably have a look at an Orchid, or dare I suggest it, an Orchid clone. These are four channel and with a better airflow than the Kayfun, the only drawback being that they really need a dual coil and are difficult to set up for single coil.
Just a view, opinions vary :-)