Why not just drop the 40K into the car you already have?
I'm pretty sure it would be quite different.
Otherwise, I think startng with a GS will allow for more buying options, will be less expensive, and therefore, will allow for more modifications.
"What would you do differently if you were to restart your SN95 FI Cobra build?"
I would remove the engine and replace it with a 600 cu. in. Kaase Boss 9. Then, I would add turbos and everything else that I did ( scaled to size, of course )with a mere 283 cu. in. engine.
I think it depends on what you are trying to achieve.
If it's only ride height, a stiffer spring rate a longer length will suffice.
If you want weight transfer along with ride height, a longer spring at the same rate, or even less, would be a route to take.
Based on your pictures, your...
No, it's actually the opposite.
For lowered cars, you want the 79-93 front struts for increased travel. The strut has a shorter body. I have these, with coilovers, on my car also.
After sitting that long, the seals probably dried and became brittle. It might not be a manufacturing problem.
The other shock may start leaking sooner than later.
At only $90 each, I'd replace both.