So it'* on both sides. Shoulda left both visible. I think that looks cooler.

or cover both

The runners may be tuned for resonance but it may just be that the engine has a high rod/stroke ratio. A high rod/stroke ratio likes longer ports to keep velocity up since the piston is moving slower. A nissian vq30 (60*v6) has very long runners as apposed to a vq35. Thier r/* ratios are 2.0 and 1.77 respectively. Same could be said for the S1 and S2.
Edit:
So I did a little searching and the r/* ratio is not relatively high (1.72) and it has a variable lengh intake manifold. If I read right it is multi-variable using a valve to change length. It has "90 percent of peak torque is available from 1800 to 5800 rpm" which would explain the longest visible portion of the runner.
A variable length intake is not to be confused with a resonance tuned intake.

What ever it is it makes my G6 GTP outrun my SSEi in the quarer mile! 14.9 vs 15.8 (stock times of course)

The old 1989 Toyota Corolla GT-* (with famed 4A-GE engine, as seen in other RWD GT-* Corollas and the first-generation MR2) had a variable induction system. At high RPM, I believe a set of butterly valves in the manifold opened or closed up. Boom, variable length.