I just realize...there were 2 version of the Ninetails, the first one with shorter back tube (with some units that have no cement inside) and the 2nd gen with the longer one which is also sold on massdrop, that which is the version that died on me without any reason. I also think that the 1st gen was the better one since I find my Ninetails being unbearably sharp in the 7-8khz region.
Anyways, my project of reviving my Ninetails is a success. I found the perfect driver that matches the stock driver of the 9way but with better response in the highs and vocal presentation, no more sharp 7-8khz peaks and lesser midbass hump. Its actually more intoxicating to listen to than the original Ninetails. Also sanded down the tubes edges because it causes pain to my ears.
This might the most natural sounding iem Ive heard atm, though this is mostly a diy iem now.