I do believe those 944s can get it done and clearly it has been proven that they can. When I had the S2 that Jake sold me I was heavily involved in research mode for the car with the goal being an ITR build. I learned a lot about them, but one thing I definitely took notice of is that there is a lot of Porsche "everybody knows" out there that needs to be critically evaluated.
A classic example is the exhaust manifold on the motors that "everyone knows is optimized from the factory. Upon inspection of the manifold, with knowledge of modern race exhaust systems in mind, it doesn't take long to see where gains can be had. But the Porsche faithful, some of them anyway, are convinced that individual components of the motors are so optimized that there are no improvements to be made. The VS crew have proved it can be done.
The two 944s in the spec lines are:
*2V 2.7L at 2635 lbs w/ 1 45mm intake valve, 162hp
*4V 2.5L at 2850 lbs w/ 2 37mm intake valves, 188 hp
I don't have cam specs for valve curtain area, but just based on valve sizes:
*2.7L has 1589 mm^2 intake valve area per cylinder
*2.5L has 2149 mm^2 intake valve area per cylinder
In comparison with my old 260Z, both cars have more favorable intake valve sizes by an appreciable margin, fuel injection, and undoubtedly a better head design than the non-crossflow L head fed by carbs. We were able to generate 176 rwhp out of the 260Z, maybe a bit more on a perfect day, so I think the 944S build taking advantage of all the rules can beat that by a favorable margin. A good deal of research would need to be done to select between these engine choices but it seems a 944 S car would be a lot of fun. If I were building a new car for S this one would be on my short list.
Not sure which I would pick. With no other data I’m in favor of finding the largest motor with the lowest specific output and build that engine, betting that it’ll have the most to gain and that theory would favor the 2.7L engine at 60hp/L. Plus that version weighs 215 lbs less than the other one, but real research would reveal the favorite.