I have just received an email from Danny (thank you), about that.
He always polite.
Hi Eduardo,
Thanks for your compliments on the service. I am glad we could be of assistance for you
we have had about 4 TC-4's crack. 2 of which were users fault. So it isn't really as big a problem as it may seem since there is about 100 of them out there with no problems. But the metal barbs do pose more of a risk of cracking than the plastic due to the taper on the threads. Also some of the earlier models were tightened a little too tight in the facftory which may have led to problems too. I did switch to a new way though which will prevent more stress on them. I epoxy the barbs in so they do not rely on tightness, but rather the epoxy will hold them tightly in so you should have no problems with the one I sent. We do have new custom barbs being made with no traper to completely rid any weakspot in the blocks. If something should happen with yours, just let me know and I will get a replacement to you. You should be just fine though. As with any poly topped block, Just be carefull putting on the tubing and make sure not to press hard on the barbs when removing or installing the tubing and you should be fine for a long time.
Thanks,
Danny
www.dtekcustoms.com