I don't know about the o rings and gaskets, but the adapter/cooler is factory only and are very expensive. If you have one that you are not going to use put it up on ebay. I sold mine on svtperformance in about 5 minutes for far too little money.
I used a Moroso kit to split it out and used a regular oil cooler. Someone makes a preferred kit, but I can't remember for sure who. Maybe Ford Racing?
FFR 6928 RD Basic Kit w/pin drive IRS ordered 02/27/09 delivered 03/21/09
'03 Terminator Donor purchased 02/23/09 arrived 03/08/09 - Ported and Polished Eaton w/4# lower and 3.1 upper. 63# injectors, BAP, Dragon TB and Plenum.