is this product smog legal for california( C.A.R.B.) and if so where is the best place online to purchase it..?

anyone..?

I'm pretty sure it is smog legal. I have no idea though, that's just my guess. This probably isn't the cheapest place to get it online, but this is what I came up with from a quick search http://www.autocarparts.com/part/269/135

anyone know for sure..?

Both the Injen IS series (short ram) and the RD seriees (CAI) are C.A.R.B. approved for the 2004 models. So, yes they are legal but only for 2004 models.

As for where to buy one, we are currently having a sale in the sponsored sales forum and the Injen IS2100P (short ram) for the xB is part of the sale. And we do have it in stock and ready to go. Link is in the signature below.