First off, all credit to PeekaySK for the concept of this deck (see: derived from) I've been playing this deck a lot, and with a lot of variations on the idea, and having a lot of success! It's an awesome deck that plays fundamentally different from any other runner deck I know of, and it's a lot of fun. For detailed info on the basic mechanics of the deck, please check out the original deck; he goes into a lot of detail, especially in the first few few comments, and debunks a lot of the "improvements" people suggest that actually go against the core concept of the deck.
The main avenue for variation in this deck is the huge suite of programs; you can go a lot of different ways with breakers and support programs, and this deck has the card slots and memory to do just about whatever! I'll just cover my changes and preferences and why I made these changes.
-3 Dagger: see below, these two are a unit -3 Cloak: This might have to do with the meta in my area, but I've found that a lot of corp decks are packing at least a few high-strength sentries (torches, archers, grims, the list goes on) and as soon as they realize I'm relying on C&D they can really exploit that, either making it so that I can't get in at all, or a the very least insuring that I can only get in once per turn.
-1 Magnum Opus: multiple copies are essential for good pacing, but I found that three was overkill, especially after I added in SMC.
-1 Netshield: even against Jinteki, I feel like this really underperformed. Monolith plus huge card draw means you can relatively easily soak a large amount of net damage each turn without much risk to the cards in your hand you want to keep. Might be good to add back in if your area is very Heavy on Jinteki players, though; mine is not.
+2 Creeper: in my search for a more flexible and reliable sentry breaker, I overlooked this little beauty for a long time simply because I had no intention of using its link ability. Once I did try it, though, I was sold instantly. Many of the problem sentries for Mimic have only one or two problem subroutines, so creeper can actually be pretty efficient (and is in-faction, allowing me to keep all the other influence cards I like better) given the generally crap state of sentry breakers.
+3 Self Modifying Code: as a program, it fits much more nicely into this deck than any other tutor, and has become an invaluable early pressure tool for me. I can throw it down for free, and then have the ability to face-check and probably break any one ICE, and most corp players will know it and slow down their pace it ice up. Combines well with Levy AR Lab Access as well to instantly have access to the entire deck.
+2 Atman: no matter how well you tune your breaker suite, there will always be that one ICE that seems to just ruin your day. While I don't play these often, this deck has the cash to set tham at pretty big strengths, giving you a very cheap route past the likes of Archers or stacked Januses (Janusi?) or whatever other problem you might be stymied by. Kind of a silver bullet for whatever pops up.
+1 Chakana: this decks biggest struggle is definitely FA Corps, and while Nerve Agent and Account Siphon put intense pressure on HQ, this card combines with your R&D interfaces to force them to either defend R&D much more heavily or try to slog through the +1 advance cost. Once it's virus'd up, it serves as an advance warning for when the corp hopes to score: if they wipe virus counters, they've got something in hand they don't want you to find.