i had this problem putting a header on my 2000 ES...
I had to cut the EGR port off and had a friend weld it in a better spot, wasn't perfect, but I got it on there after applying lots of elbow grease
Not sure how the OBX fits, but this was one of the "ebay" headers. Take your time with the EGR tube, there is a small clamp on the driver's side of the engine that you should take off to give yourself some more wiggle room.
yeah, 'ebay' header systems have this problem sometimes regardless of if its a 1.8L or 2.0L (which share the same head, but are oriented differently as the 1.8L has a shorter deck height)...it takes a little luck on if you'll get the right EGR location...but luckily its something that is relatively easy to custom fit if need be...