Yeah, he had a Nissan sports exhaust.
Legalis may flow slightly better looking at the exit of the uffler to the tips - each tip comes from its own hole in the muffler as opposed to the Nismo which has one hole for the two tips, BUT what is the radius of the hole/holes? Is the Nismo single hole actually a larger area than the two Legalis holes combined? Also, since the piping is the same, it all comes down to the design of the baffling within the muffler, and ripping open a Nismo muffler that can no longer be replaced does not appeal. You could of course get their flow measured if you really wanted, but I like the Nismo for the tip design and the sound which has more character than the Legalis IMO.
Can't go wrong with either though.