It is not worth. You paid 250 Kas for a firmware + heatsinks .... to make 3 or 4 kas more and this will go down for sure. So how long do you need to get this 250 Kas back? Same for purchase. $349 = 3500 Kas, how long need a KS0 to mine 3500 Coins and the difficulty increasing everyday?

Don´t buy Kas Asics, always better to buy the coins because of the increase of hashrate and this will continues. Keep in mind you can only mine Kas with this Asics