That was the only part i understood

 

Velo .... I have one also and I've also seen theories pointing both ways, but I looked at the Reynold's number that represents the airflow in my intake and it is so far turbulent that it seems impossible for the swirl caused by the spacer to last more than an inch. The only thing that I see as possible is that by adding volume to the IM that the resonant frequency is lowered a little. Since the intake, TB, spacer and IM are not tuned together, there is very little chance that the spacer will cause resonance in the IM that will improve power.

 

there's only one way to know for sure.

 

True, but I'm not going to waste time, money and effort on with/with-out dynos on a part that I don't really think does anything. By calculations, it can only add restriction.

If you do the dynos, let me know what you find!

 

Working backwards, we've already addressed 4-2-1 vs. 4-1. If you mainly keep rpms above 4000-5000, 4-1 is better. 4-2-1 is better for 2000-5000 rpms. The material makes very little diference in power. Theoretically, the ceramic coating keeps the exhaust stream hotter and thus faster, but I wouldn't expect the difference to be measurable on a car that is not highly modified (forced induction, high compression, etc.). Primaries can be larger even if not noticable by eye leading to less restriction. Improved collector = less restriction.