[JohnCena]

Originally Posted by Drillslinger

The N55 Mid-pipe is essentially a secondary Cat delete.

See here: http://www.1addicts.com/forums/showthread.php?t=651547

Exactlly

The N54 midpipe is resonated and catted

The N55 midpipe is only resonated.

Originally Posted by MrRoboto

^^So aside from the sound, do you feel any power difference, does it seem to rev more freely?

Seems to open up slightly. now that the miestershaft is in its NIGHT AND DAY power increase.