This is exactly the kind of project I love. For my adult life, my car hobby has been fulfilled by buying slightly needy cars and rebuilding to my desires, mostly muscle cars, and trucks. My problem is that I never sell anything, so I cant say I have ever made any money, but it makes a good story to my wife.
I bought a 911 about 5 years ago that similarly had needs, but not as extensive as this turbo. I got a rude awakening, 911 parts are ridiculously expensive and the value of buying an incomplete or needy car disappeared. In the Porsche world, it seems that you are 10’s of thousands ahead buying completed cars.
That said, BAT seems to be a reasonable sourced to go for representative prices. Some would argue that BAT prices are somewhat high, but auction results are what they are. BAT usually doesn’t have non running cars, but there is a pretty good selection of 930’s sold in the past year to get values of what it is worth completed.
This should be a search of recent 930 sales:
https://bringatrailer.com/porsche/930-turbo/
Lots of “normal” 930s in the 50-70k range. By normal, I mean not crazy low mile, not highly modded, not slant nose, and with proper original engines in good condition.
If you go backwards from there with the repairs needed to yours, you get to a number that approaches scrap value. I know it doesn’t make sense, but that seems to be the economics these days.
I would be interested, but I’m afraid my number would be insulting.