Dave,
I can't speak to the windshield surround or Targa repair as I was able to save mine from full replacement with some tedious metal work. I can however help you with the floor pan replacements.
I recently posted a complete review of my 1983 X rebuild which you can find here:
https://dl.dropboxusercontent.com/u/...20X1-9 s.pdf
Below, I've excerpted the part you need:
My floors looked like this:
I sourced replacement pans from Ricambi-Automobilia on eBay (they are in the Netherlands) - I think I paid around $400 US for the pair. There are less expensive alternatives on eBay but at the time, the difference in cost didn't justify the difference in quality - the Ricambi pans were much better formed. I just checked eBay and the C2C pans have been drastically reduced in price - only $80 a pair! They must be trying to get rid of them. For that price, they may be a reasonable choice. Alternately, you can try to form your own but I chose not to go that route.
http://www.ebay.com/itm/1973-88-Fia...m2373328053:m:mqCCP8K3DgWUa1QNcCwIKjQ&vxp=mtr
As I was just learning to weld, I decided to engage a local mobile welder to tackle the job. I was afraid of warping or damaging the metal with my rudimentary MIG welder. I am glad I did - he did a superb job for not a lot of money. We plasma torched out the old floors and then, begin the process of "fitting" the new ones. Since the rot extended back to the cross beam support, I was glad the Ricambi pans gave us plenty of metal to work with.
Through a process of hammering and spot welding, we reached a very good outcome:
As you can see from these pictures, we went with the spot weld theory and worked slowly as to give the metal time to cool to avoid warping and hot spots. The "fit" between welds was very good - i.e. the metal laid well and was tight to the structure.
I finished all the seams (both inside and outside) with 3M Automotive Seam Sealer and then primed and undercoated.
I sourced new rubber drain plugs and used a hole saw to create the right size hole. Then, I installed an inexpensive foil / foam material for heat and sound deadening.
The end result is perfect. Quiet, leak free, and identical to the original floor clearance.
I hope this helps!
Good luck!
Ed
Austin, TX