Honestly, I’d go the full cyborg route, like in Ghost in the Shell. This would be my first step toward adjusting my consciousness to existing within and controlling an artificial environment, ultimately aiming for fully uploaded consciousness. I’d want to exist as a cyborg for a couple of decades, then I want to be uploaded into an autonomous space probe with as many sensor types as possible and left to explore the Universe (+/- relativistic speeds, I don’t really care). BUT I’d also want the possibility to erase myself, because I most certainly wouldn’t want to live forever. At least, not as I see it now. This is the purely sci-fi version.

In the realistic version, a cybernetic eye and a logic co-processor to increase my background process bandwidth. Sure, a brain-computer interface would also be nice, but I somehow suspect I’d get nostalgic for the clackety-clacks and would most likely revert to analog interfacing after a point (for which I’d like that “fingers within fingers” prosthetic from GitS).

Unless, of course, Musk (or any other such) will be handling said cybermods, in which case none, thanks. I’d rather just decay and die as a basic human being than have such people tinker with my bits.