The kits will come with all the jetting for usually 3 different hits. The NX kits come with 35HP, 50HP, and 75HP jets already in the kit. Most kits are VERY complete right out of the box. The fuel rail adaptor is just a little gadget that saves you a step.. Several of our sponsors carry them in stock.
Yes, there are direct port kits available for the focus, they are considerably more time consuming to install as well as more expensive. NX or NOS have them ready to go. There is no real advantage going with one for the smaller hits of nitrous. However, with a motor built for nitrous they offer more precise control of delivery of both fuel and nitrous to each individual cylinder in the motor.
Simply put, dry systems rely on tricking your stock fueling system into suppling enough fuel for the nitrous being applied. This works fine for smaller hits of nitrous, as the stock fuel system has its limits....Whereas the wet system supplies its own seperate fuel source to combine with the nitrous... Any detailed questions on this, feel free to PM me.
Speed is only a matter of money; how fast do you want to go?