It's tough to nail down a hard FBO n54 dyno number with no race gas. I am seeing in my Google searches of n54tech, BMS website, and 1addicts anywhere from 378/385 to around 410/420
http://www.n54tech.com/forums/showthread.php?t=13933
BUT....Terry's dyno with WW meth is here:
http://www.n54tech.com/forums/showthread.php?t=13097
I think I need to get a meth kit and hit the dyno to nail down a 400 number for the N55