why not NX? I like nitrous outlet but you can get a plate kit for the same price as a nozzle from nitrous outlet. NX also has amazing customer service they helped me quite a few things. I had logs from when was getting my kit together from their chat room.
For purge you should only need a 4AN unless you upgraded to the 6AN line, the pressure gauges will be all the standard 1/8 sender thread like all general sending units unless you want an inline. You also dont need either of those pressure gauges if you plan to add your own auto meter or gauge of your choice.
I also have some odd ball shit left over you can have like a new bottle gauge if you wanted it and some small fittings.