In fact, the human DNA actually stores more prominent memories of a body(meaning sicknesses and stuff or other dangers) to be able to protect the body more.
Please provide a source to support this claim or I have to call BS. As far as I know, your DNA doesn't change because of illnesses (outside of very, very specific illnesses that themselves alter your DNA). Your immune system learns from and adapts to diseases you suffer, through production of different types of cells aimed at fighting specific threats, but this isn't any DNA-based change. You'll get epigenetic changes as you age, but those aren't changes to the coding itself.
Therefore that brain being also you in 100%.
No, it is simply identical to me, but that does not make it me. The trick here is that two things can be identical, yet distinct. If I copy a file, the copy is exactly the same as the first file - but the first file still exists separate from the new file. From an outside perspective there may be no way to tell us apart (outside of us not inhabiting the same location in space-time), but from MY perspective, I am me and nothing else is, and my perspective is what concerns me (as I said, continuity of experience - the moment it is broken, I am dead and a new being has taken my place, even if that new being is exactly like me and thinks it is me).
Consider the following: B - B. These letters are physically identical, they have the same meaning and uses - but would you say I only typed one letter? Is that the most accurate way to describe it? Or is the more accurate way to say that I created two identical, but distinct, copies of the letter "B"? If a perfect clone of you is created, unless you are seeing through its eyes and experiencing what it experiences, then it is not you because the instant it begins to exist your experiences become divergent and it stops being identical.
Also your car metaphor does not stand to a cellprinted organ or limb or whatever. Since those are created by your own cells, just outside your body those are actually belong to you.
To make the car example, if you replace all parts of a car it might be a brand new one, but if you take the broken metal, melt it and create a new part from the old one and use nothing else, it is still the same car. You only use the very same material what built it up in the first place. you are using the same atoms and in the same form, therefore it is still the same.
Ah, but these are two different things. Cell printing uses your cells as guidelines, as an instruction manual, but it is using new material to make new parts all the same. The machine isn't breaking down your stomach and rebuilding it, it is taking a piece of your stomach and building a new one around it based on it. Even if it was simply growing a new stomach from your cells in a petri dish, however, that still doesn't make it the same object as the stomach currently in your gut, no matter if it is absolutely identical or not. You'd be able to very, very clearly demonstrate this during the replacement surgery, as one stomach is taken out and the other is put in - clearly, two different organs here. That they are physically identical does not stop them from being distinct objects - their coordinates in space-time will always be different.
The real question here regarding identity is whether it applies to the whole or to the components. I think it applies to both. All things are just assemblages of smaller things - when we say we create something, all we're really doing is taking already-existing things and putting them together in a certain way. I don't really create a table, I simply arrange four long pieces of wood with a flat one in a certain manner and this new arrangement we call a table - because discussing these components is now most accurately done by including their specific arrangement with each other rather than treating them as solitary objects. But this arrangement itself now exists, in a specific location and interacting with things in ways that its components would not on their own. However, when you detach a leg from this table, the arrangement is lost - the table is destroyed. Re-attaching the leg doesn't stop the table from having been destroyed - it means you're assembling a new table with the same arrangement and components the old one had.
The fun part is that you CAN replace parts of the table and have it be both the same and not the same table, depending on whether you're looking at the components or the whole, so long as the general arrangement is not destroyed at any point. From the perspective of the whole, I am the organism that has been growing for the last few decades, because the organism isn't defined by its parts so much as how those parts interact (and the continuation of that interaction). From the perspective of the components, I am not at all the same person, as the vast majority of the matter making up my body a decade ago is no longer present in my body, nor do I think or act in exactly the same manner I did then. Both perspectives are correct.