Both sides have legitimate points, and from an objective point of view, I wouldn't be able to tell you which sounds more viable. I got a question; the telepathy growths, they are apart of the host's body. Which tells me that they need the host's body to supply them with nutrients to survive. And if they were damaged, the host body would need some sort of blueprint of how to regrow tissue to the Telepahy growths, right?

The telepathy growths themselves could have their own set of DNA for regeneration and what not, but i'd think the host body would also need some direction as to what to do with the growths. Would there be anyway for the Guyver to install those without altering the host's DNA?

yeah, I'd think if like a organ transplant.

the telepathy growths could actually be some kind of neural tissue generated from hte hosts own DNA library.

Thats a good point since we know that the Guyver assimilates DNA on initial blending. And if it was generated based off of the host's DNA library, then that would mean it wouldn't be rejected since it's of the same genetic code as that of the host; and its its body would recognize it as 'friendly,' yes?

It wouldn't need to be rejected. Parasites have a long list of techniques they can use to bypass the human immune system. There are over 40 methods available. The immune system does not reject everything. For instance, Chimerics are People that have two sets of DNA in their bodies, organs, or patches or organs that technically belong to another person. A baby in a mother's womb is technically using a parasitic technique to avoid the mother's immune system, the placenta akin to a cyst to isolate the two of them.

If we take a bit of every description of the telepathy growths from every incarnation of the Guyver, even the word 'growth' which has been associated with various infections, the telepathy growths are more like an implant of some kind that an immune reaction fell short on.