The rpm II is one of the best on the market. While others may claim there are equals or close enough, the most powerful NA normal street setup built on a stock shortblcok i've seen wears an rpm II.
I had one a few years back that i got like new (and it was literally like new) for $400 shipped.
So if this is really the best intake for your setup, keep an eye on craigs and ebay and get the real thing.