Any chance of getting that part number, went in to get one today and they told me that its a whole unit not just the stud.
Another part i will be changing because of the removal of the heat exchanger is the fitting at the back of the block, on the 25 it has a straight pipe that comes out, a hose then joins that to another bit of pipe that has pipes for the throttle body hose and heat exchanger hose and a bracket to mount it to the back of the manifold, if you use the one off the rb30 it is just the main pipe with a pipe running off that for the hose to the throttle body, much easier then the 25 set up, the part number is NI-14075-42L01 price was $59.10, not cheap but well worth it instead of dodgy fixes i think.