355 Found another one, looking for advise

After 2.5 weeks of back and forth with a dealer in Seattle on a 99 spider F1 with all the "stuff" done, good price, he Texts me on Friday and says it's sold to someone else. WTF, I was so disappointed. Guess I was asking for too many Pictures.

I found another, right in my back yard. Went and looked at it today. Had a couple questions hoping you guys could help with. It has headers on it. Hard to see so not sure what brand. There is no header heat shielding. How big of a problem is that going to be? I can add something later. Read a bunch about the Cats, Muffler shielding here. There are no air rails on the header, nor any of the associated parts. It's a Canadian car with KPH speedo, Celsius temperatures and sold in BC. Did we Canadians not need the air rails?
The door sills have some ripples in them. I suspect it's the "rusty door sill" issue you guys have been talking about. Is it an easy fix? major problem? looks like the original tires. Seem like every car I look at has old, hard as rock tires on them. What gives? It not like it's a good thing to have original tires. Has a little nose rub under the front. Other than that it a beauty. No sticky, no warp interior, clean title, looks well maintained, keys, manuals. Just need to get the service records, A PPI and try to make a deal. His price is WAY high. Need to get him down to earth. Otherwise it's a no go.
Thank again
Mike