I tried this string as a cross for my gut too. I'll just copy and paste my thoughts on this string from my other thread. Why am doing it again? Because I hated the string this much...
Tecnifibre X-Code 17 as a cross is disappointing on various fronts, I was mad weaving them, and I stay mad playing with them:
1) It's $16 a pack. I'm glad I only got half a set at a cheaper price. Because I don't know who in their right mind would spend $16 on a set of (crap) polyester.
2) It doesn't string on well. The coating has a texture consistent with semi-dry paint. It's rubbery, almost sticky to touch. Imagine what that's like when you're weaving the crosses on gut.
3) The semi-dry paint/rubbery coating doesn't seem to facility the sliding and the snap-back of the gut mains. It doesn't take a lot of strokes for the mains to get all bent out of shape. It's almost as if the rubbery coating is "trapping" the mains in place.
4) It frays like a cat would lose fur.
5) It actually plays less stiff/softer once the sweet spot starts fraying. I'm telling you, the coating absolutely kills the strings.
6) Probably the most important point. The premise of the Tecnifibre X-Code is to bridge the gap of multifilament and polyester: providing the softness/arm safety/comfort of a multifilament construction with polyester playability. But it fails miserably. It's soft but it's not the softest by far. Polystar Energy and MSV Co-Focus are both softer and they're half the price.
7) Lastly, it retails at a ridiculous $16!!!
This is seriously one of the worse strings you can buy from a economical and performance standpoint. That stupid coating ruined the strings. It doesn't do anything a polyester is supposed to do from my experience. It does one thing that's just OK: being soft. But it's not even that sof. There are a ton of strings that'll fulfill that requirement and less expensive too.
It does have a good function. If you ever want to know where your sweet spot is, these strings will tell you. But then again, you can get Tecnifibre E-Matrix for $5 for that purpose.