I was going to ask the same question. Don't suppose you've bought one have you?
I also wondered about the 'limiter'.
I found a cdi on ebay before, it wasn't for an NSR, but at the bottom of the listing it stated that they did make them for the MC16. I emailed the guy and he informed me that they didn't actually produce them for any NSR. I'm sure his name was Sky.
I guess the moral here is to be careful and as Stephen says, be prepared to waste £80.