$50 CAI's on Ebay
 

has anyone had first hand experience with these? Some of them come with "Nismo" filters and appear almost identical to an Injen or Aem.

Also I noticed there is a new part number for the full Nismo intake. Did they make some improvments?

Any help would be greatly appreciated.

Like most things, I think you get what you pay for. Many products on E-Bay are knock-offs and the "NISMO" stickers are counterfeit. Usually you can tell by the price.

The engineering and construction quality is often below par, and depending on the part, can even cause damage to your engine. Often the same part is re-badged to reflect the high-performance divisions of various car firms, just to have you believe that the items are authentic, and desireable. Occasionally, you get something that is a close facsimile, at a decent price however.