Notice all these designs share 1 basic similarity. a long and a short runner. While I understand the engineers are trying to acheive the best volumetric efficiency for each tuned length, it's a tradeoff at best. Long tubes work at peak efficiency say around 3000 rpm while the shorts at say 5000 rpm (hypothetical). The fact that both are being used at high rpms may cancel each other out in terms of intake pulses reaching their proper points on each set of runners. I don't know if this is a consideration at all.
The FSVT intake is on the right track to being a perfect design. Picture the pivoting part as having tubes that slide inside the stationary tubes. You now have the perfect intake! A variable runner intake that would be effective through the entire rpm range! Extended at low rpms and as the rpms increase, it retracts into the stationary runners. That design might actually work!
