hi does anybody know what this means?? "electric dual-mode muffler" i found this in the specs pages at infinitihelp.com for the 2003 sedan

 

I don't know where they got the "electric" part, but the sedan muffler does have a flapper in it that opens up under higher exhaust flow. The flapper helps improve low end driveability and upper rpm breathing. The old Skyline GTR, 2000+ Maximas, Sentra SE-R/SpecV, and lots of BMWs and Mercedes use the same technology.