are all be series fuel rails the same? more specifically, will a fuel rail off a b20b intake manifold fit onto an ITR manifold?

 

No, they are not all the same. The thing you have to look out for when using the R manifold is the location of the stock FPR. I'm not sure where it's at on the B20 rail, but the old JDM B16A fuel rails won't work on an R manifold because of the FPR interfering with the TA connector.