To tell you the truth parts are gonna be impossible to find if you decide to swap a RB25 neo. I currently have a RB25 and it cost an arm/leg to get parts for it (located in Japan). If you got any questions about RB engines you should check out
http://forums.skylinesdownunder.co.nz/ for more info. Then search for Zilvia members on here who actually had a RB25 swapped into their cars. Good luck!!!