I know you done a lot of great work on your ride so far, and budget is key, but my suggestion below...
Pull manifolds and wire brush or media blast. Then paint everything with good quality high temp paint and put back on with new gaskets.
Paint the studs and nuts too or go to ACE or True Value ... Etc... And get the brass nuts. The fittings that are welded over from the air injection pull those out and replace with 1/4 pipe plugs, so when you paint the manifold it looks much more professional.
Reset all your exhaust. Remove the Y pipe and get those bells reshaped or cut and replace as a temporary measure until you can get the duals on.
Get a proper wire loom and work on getting the wires secured correctly. You have good quality red 8/9 mm, yet they are just flopped in there. All this is basic elbow grease and don't cost much, yet makes the under-hood look much more professional.
Check your size but I think the nozzles were 1/4 pipe. Attached are the ones I get, 1/8, 3/8, 1/2 inch also available. When I was doing the show cars I would just buy 20 or so at a time. Buying these at hardware store gets too expensive.
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