This diffuser can be found on APR Performance's website below, and will fit WRX/STI's from 02-07.
APR Performance - Subaru Impreza WRX Rear Diffuser
This diffuser will fit MOST rear aprons/spats, including the 04 and 05 JDM rear apron with little or no additional modification. I am installing the FPR version on my 04 WRX with the 04 JDM rear apron, which is already installed. Although APR does include instructions with the packaging, it never hurts to go into more detail. I also found the photocopied pictures included were very difficult to see.
If anything is confusing or unclear, feel free to PM me, and I will try to explain it better and clarify it in this article.
Tools/Supplies Needed:
Metric Sockets, wrenches, and allen wrenches (hex keys).
Power Drill w/ drill bits
Dremel - optional
Misc hardware explained in the how-to
Tape
The diffuser is in two pieces with three adjustable mounting arms loosely bolted into place. Also included was a set of instructions, some brochures, and a package of hardware.
