Insurance rates are based on a lot of different factors - age, driving record, state/city/neighborhood, sex, etc. Someone else's insurance rates will have no relationship to yours.
Your best bet is to call your insurance company and ask them how much it would cost you to insure an NSX like the one you might buy. They can give you an actual quote for YOUR circumstances, and it will be a lot more meaningful. Yes, you can do this before you decide to buy one - and it's a good idea.
You can also get an idea by trying one of the web-based insurance quoting services like
http://www.insweb.com