Not sure about series 1 but I think it's the auto series 2 that has the GTT rear.
Hopefully chuckie sticks his head in here, I think he's quite knowledgable.
Front upper arms should be 33gtr and rear upper arms any R33/S14 upper arm should fit (I've got R33GTSt rear upper arms on my auto s2).
Swaybars, 33gtr should fit front and back (auto s2 has a wider cradle and it's a much tighter fit). Stock 33gtr swaybars are an upgrade or just go with Whiteline (I have them in my 32).
Never heard of a front underfloor reinforcing bar..
Tension rods.. do you mean castor rods?
Don't get too hung up on the whole "Nismo" thing, there is often better aftermarket stuff for cheaper.