I personally use this strat when I don't think I can beat the zerg in a straight up game(LOL), but their are some questions i'd like to know.

Like, most sites say to do a 18 fact, when you could have it out at 16. Now, I think its 18 so you can pump rines constantly, and get ports up at same time, while if you 16, and still make rines, you make one port, kinda have to wait, then make another. So for a TvZ 2 port is it 18 fact or 16 fact?

Also, after he gets up spores or w/e, basically stopping the wraith rush, would the smoothest transition being switching to SKTerran? I mean, usually you get more rax up and expo while atking him, now you have 2 ports, one already with an addon, would it be best to lift fact and get sci facil?

And one more question not really pertaining to 2 port. When you get your 1st ebay, +1 weaps or armor? Mutas +1 kill them fast, and vs lurks people say +1 armor b/c its 3 hit kill. Well, if you stim, its 2 hit kill again . Which is better to get first, or does it depend on zergs build.

Thanks in advance!

The success of the 2 port wraith rush will depend on the zerg scouting it or not, so i tend to do it on maps where you can wall in (bluestorm is a perfect example as you can build a lingproof wall on both positions), so i don't think you'd need any more than a marine or two, constant pumping seems like a waste. Also, if i'm doing this i like to use my factory to make some vultures (it is particularly sweet if you can lift the fac to his main behind his sunks and prevent mining), since they own drones and speedless lings hard.
Yes, if you opened 2 port wraiths, there is no reason not to go SK.
Always always always go +1 weapons against zerg. Don't listen to people who say +1 armor against lurkers, because they don't use stim (or, in other words, they're noobs).

You really, really need the marines that prevent that fact from getting put down quite so early. Yes, if your opponent is not very aggressive, you'll be fine with just a few, but unless you have a very easy wall in (which is why this strategy sees more use on wall-able maps), you need to delay the fact (and resultingly the ports) a little so that you have a good half-dozen marines up in case he decides to probe your ramp with a dozen or more lings.

Yeah, sk is the natural follow-up, you're already there, basically, don't forget to put down engineering bays for upgrades while you're wraith microing. As far as the +1 weapons/ +1 armor debate, both sides have valid arguments, and yes, it is very possible to kill lurkers without stimming the entire army, just very micro intensive. I generally go +1 weapons followed quickly by +1 armor, however, because I usually avoid lurkers alltogether, irradiating or moving around them whenever possible.

Yeah like Bazse said, its really only doable if you can do a perfect wall in because as you mentioned, in order to be able to make enough marines to make the build safe you delay the wraiths a ton. I like doing standard rax FE and then going 2 ports just because it gives me a lot more resources to work with and has that deception. Although ur wraiths come out like right after mutas, I do it more for fun then for seriousness, as id consider it a cheese

If Z invests in a lot of lings, then pulling 3 scvs to keep on your depot keeps you ahead and secure.

+1 weapon is always better. There is absolutely no reason to not get weapon and not stim. You get double the attack power +1 attack whereas if you get +1 armor and don't stim, you'll take 1.5 times longer to die but you do less than half the damage.

If you see <5 lurkers and you have a couple of control groups of rines, there's no reason to avoid them. Especially if you have the luxury of defensive matrix, you can probably take on 6 or so lurkers with ease.