None what so ever.
Twin plugs can help give improved flame front characteristics and more complete fuel burn in high compression high RPM hemi head race engines runing on exotic fuels and in stock engines might improve the combustion of questionable quality gasoline in some certain circumstances but otherwise no REal measurable gains for the REst of the motoring world to make it worth the expense unless you like it.To say it in fewer words,,,,
...Some of the larger 2 valve Ducati's have 2 plugs per cylinder as well.Scott
well my fireball dos'nt have twin plugs ..man i really like the compression release and would'nt giv it up for another plug.
Hmm weird the Classic 500 in that video deffinately has Twinspark cast on the cover, but on the RE website here in India they only list the 350 as having twinspark and that same coverplate doesn't have twinspark on it on the 500 model only the 350