The bi-modal air intake has a valve that increases the amount of air sucked into the engine depending on throttle position and engine revs for extra power. When closed, torque (or pulling power) is enhanced at lower engine speeds.
Isn't that the job of the throttle body? A valve that increases the amount of air sucked into the engine? (Or pushed in to be absolutely correct).
What Kiddo said about the X pipe is spot on too. But the term X pipe only refers to the true X pipe, not a merge. People call a merge an X because it looks like one. A proper X pipe is shaped so that it actually directs the exhaust flow to the opposite bank, where as a merge is just an opening that acts like a balance tube. When done incorrectly, the merge is actually a restriction as it reduces the pipe size at the merge.
One exception is the Sureflo merge, it acts more like a pressure wave termination box than a merge anyway, whether by design or by accident, it actually works rather well.
Sorry to ramble on, but it's a bugbear for me when people refer to something that it is not. Especially with exhausts.