Go with the CoPs set-up, much better in the short, and long run.
I did a write-up awhile ago
https://www.ninjette.org/forums/showthread.php?t=241339
Like @
InvisiBill, I also run this set-up on both of my EX500s, and I did on my PreGen 250.
I didn't bother with installing anything extra, no load resistors, etc. Just be sure to get wiring harness with the coils.
FYI the Ninja 300 uses CoPs from the factory.