I would be interested in hearing the other thoughts on this, but IMO, I dont like the intake manifold on the S4+ or the size of the valves.
I haven't done any research to back this up, and it is still theory at this point in time however.

Compairing the intake ports/valve sizing, and intake manifold on the 85/86 32V engine, to the equivilent parts on the S4+ cars.
I think they were closer to the mark with the 85/86 engines.
The reason I say this is the 85/86 engines had slightly smaller ports, now this may limit max flow a tiny bit, but max flow isnt always what you want, ESP in a street car. If you keep the ports smaller on a street engine you can in alot of cases see an increase in HP. The theory behind it is that though the air is restricted alittle the air going in has a much higher port velocity, this can in some instances help the car breathe. But the main advantage to a higher port velocity is that the air going into the combustion chamber maintains greater turbulance. This keeps the fuel atomized and prevents it from puddling inside the chamber. Looking at the stock S4 HP charts compaired to the S3 charts, the S3 has a smoother hp/tq lines, where the S4 tends to spike up and down.
As well the tests which Louie and Porken have done to the S3 engine proves it is not prone to knock/pre ign, where with the S4 alot of them ping esp in hotter weather on the stock ign map, sometimes with lower grade fuel.
I feel that Porsche knew this fact when they made the S4 engines. The reason behind this is that the S4 engine had the addition of quech chambers in the cylinders, where the S3 engine did not.
The reason I feel Porsche did this is that they found with the intake manifold and size of the ports the air/fuel entering the engine was traveling at much too slow of a desity and was puddling/deatomizing causing a leaner AFR, they then added the quench chambers to add turbulance into the combustion chamber. IMO it is a bad fix as when the quench comes into effect some puddling has already occoured.

I would expand on this abit more but I have to run, I have a plane to catch.

 

Depends on what your goals are. Short versus long intake runners each have their advantages.

Todd is going for the shortest runner possible, I would guess the same thoughts went into the ITB setup Louie designed.

This is probably why Porsche designed the S4 intake the way they did. Few short, few long give you that really broad curve. Some cylinders have lower end torque, some pull harder up top. This is nothing new, Can-Am cars were playing with this in the 60's:

 

Yes, The horns used on the ITB setup that Louie and myself have are on the short side.
The stroker has enough TQ, so the short runners maximize top end.
Example on a small motor:

 

Pick up a book called "Tuning And Modifying Engine Management Systems"

There is a great chapter in there all about intake manifold designing and even provides you with formulas to calculate the ideal runner length if you are looking to either make a setup with more torque, horsepower, or both combined.

I was using it to do my individiual throttle body setup on my 944. Unfortunately that project was cancelled since I'm selling it. I may pick up another set of the same motorcycle throttle bodies later and see what ideas I can get with the 928