I've found that 550F headers have not been too difficult to find, and has been reasonably priced: $150 - $200 or less depending on condition. Admittedly it's been a couple years, but I sold a complete exhaust with a decent muffler for $200 5 years ago. Maybe the last couple years have seen an increase, but I don't think the headers were too hard to find and I imagine they're out there still.
Similarly, I had a few exhausts plated over the years in Phoenix and the most it cost me was $250 or so, again a few years ago. I had a bumper for my '64 Valiant straightened and rechromed for $300. Chrome pricing depends on where you are and the environmental regulations. Phoenix, I'm guessing, is at the low end of the cost spectrum -- but it might make it worth it to send it there or elsewhere and pay for shipping to save money overall. And I've never had a plating place tell me they couldn't do exhaust.