i guess the bigger question would be is the MAF sensor the same size on both cars in question. the MAF sensor hole on the intake would need to match up for that piece to fit and i'm fairly certain the air filter and box would fit.
well now it looks like the one for the 04 3.0L doesn't even have the MAF sensor plug into the intake, this seems weird to me.
http://www.afeintakestore.com/143755...85-e86-z4.html