Kooch,
I cannot answer about whether the New Jersey inspectors require
horizontally mounted license plates.
I do know that a lot of guys who run side mounted plates also
want to remove their turnsignals. While I agree that turnsignal
removal makes for a cleaner look on show bikes, I cannot condone
running a bike which was originally built with turnsignals
on our streets and highways with the signals removed .
A friend of mine suffered extensive injuries in a motorcycle accident
which he believed was due to the confusion in the driver behind him
misunderstanding his intensions. He wanted to make a right hand turn.
He made the hand signal for a right hand turn, but his taillight/brakelight
was mounted on the left side of the bike above his sidemounted
license plate. His antique Harley knucklehead did not have turnsignals.
The fellow behind him thought that the pulsing brake light,
(which he activated more than once between each downshift)
was a left turn signal indication, and tried to pass my friend on the right.
Broken arm, broken leg, broken ribs, totalled out bike.
We have to share the road with folks who are old, half blind,
sometimes drunk, talking on cellphones, adjusting their radios,
drinking coffee, putting on makeup, you name it, they do it behind
the wheel of their four wheel cages. Make sure that the idiot following
behind you can see and understand what your intensions are as
you ride your motorcycle. Be sure that your rear lighting works at
least as well as the manufacturer designed it to.