I'm looking for anyone that has done a successful WRX swap into a 2.5rs. I have talked to a few people that say that the wireing and transmission need to get swapped too. Please forward any information that can help me out.

There is a section in the FAQ covering engine swap requirements.

Yes, the harness and ecu need swapped, you may not need to swap the transmission, you will need to swap the front cross member.

US WRX or Japanese WRX?