for anyone doing an EARLY 04 sti trans, (stubbed axles). mine has always leaked, after further research, not only do you have to remove the stubs, you also have to replace the "sundial" or differential retainer on the sides of the transmission for our male style axles to fit properly.
Sundials (retainer differential) 38342AA161 (2) dealer claims same l/r
O-rings 806900150 (2) may not be required but ordered to determine.
Numbers above for a 2005 STi. Local dealer claims sundial part numbers are the same for '02 through '07 model years.
Having the above part numbers should allow a "pinned" '04 US STi to be converted to non-"pinned" and direct fit a STI or LGT front axle. The stub shafts will require removal from the "pinned" transmission's differential. Be sure to review the appropriate Service Manual for installation and adjustment procedures.