Update: I've had a few days to evaluate the car's performance since installing the tubes along with Cosworth drop-in panel filters (
Cosworth High Flow Synthetic Air Filter; For Twin Air Box Applications INFINITI G37). My perception is the idle is quieter and the engine surges more smoothly and progressively to 7K . No noticeable difference in power. I'm very pleased with the improvement with the combination of the Mishimotos and Cosworths.