In theory, I wouldn't hesitate one second to replace a substantial amount of my body with chrome — legs, arms, internal organs, eyes, etc — but I think actually going through with removing a healthy bodypart that I didn't hate and has served me well enough would be difficult. Nevertheless I don't think I'd really regret having gotten it done, so it'd just be like any other big scary surgery.
I don't think I'd want to do whole-body biotech upgrades like increasing muscle density or nervous system efficiency or whatever, because that effects a lot of things, so it's both more invasive and could have a lot more accidental unintended consequences. I'd probably start with replacing my left arm with a cybernetic one, since that's my off hand so I won't miss it as much if something goes wrong. Then use that as a platform to tinker and experiment and decide if I want to go further.
As for what kind of chrome I'd want to chip — I want the simplest, sturdiest, most robust thing that can possibly work, something I can understand as completely as possible, something that I can at least somewhat repair and upgrade myself, something that's well-known for reliability. Nothing super flashy with a lot of moving parts so its flimsy and unreliable, I want the PineTime or ThinkPad T420 of cyberware. And of course I'd flash it with open source firmware and remove all the corpo software and tracking I could!
I'd be a lot more careful about modifying my brain, for two reasons.
First of all, my theory of personal identity / consciousness is that the sense of coherent, singular identity doesn't come from a single, constant set of essential characteristics — whether physical or psychological — but from there being a sufficient resemblance between yourself prior to any given change and yourself after any given change, and a coherent self-narrative pathway from one to the other so that you can reconcile the two. Yourself at 20 and yourself at 35 can have completely different interests, beliefs, neural pathways, memories (our memories falsify over time, after all), and whatever else, but it's still you — how? Because you got there by a step by step process where you remained you between each change, and so by the transitive property, you're still you at the end, even if you're completely different now. If A ≈ B, and B ≈ C, and C ≈ D, then A ≈ D, even if A and D are completely different, because they've got this web of other things connecting them. Thus, if I'm going to maintain my sense of being myself, instead of accidentally killing myself off, I'm going to have to do any modifications of my brain slowly, step by step, and adjust to each one before getting the next one.
Which works out, because of my second point: if an implant in your brain goes wrong, its WAY, WAY, WAAAAAY worse than if something goes wrong with your body. Like, brain damage is no joke kids, I'm dealing with the fallout of it right now and it is not fun. And of course, as we all know, tech fails. A lot. It's buggy as shit. It's often pushed out the door before it's ready. It has vulnerabilities. So I'd want to keep the brain mods minimal if I did any at all — tried and true, tested, resiliant, as simple as possible, and not connected to the 'net.