Tarmac may be able to import genuine Nismo bumpers for you.
Shine Auto do some very good quality replica's of Nismo bumpers for a lower price.
I'm pretty sure that bumper you have shown is a rip-off of someone elses.
You get what you pay for with bodykits. The money you on the initial purchase cost is often outweighed by the amount of work needed to make a badly produced bumper fit.
That said, a Shine Auto bumper will cost you the same as what that ebay guy is charging, and their quality is pretty damned good. (I've had 2 without a single issue).