Unicorns and leprechauns exist in the same place as actual performance gained from Rube Goldberg exhaust plumbing. There might be an advantage at some very specific RPM and load ranges, but anyone except pipe dreamers and other believers in chemically enhanced life experiences ought to know better.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!