Quote Originally Posted by Mechie3 View Post
Knuckles are wider where it mounts to the strut. Not sure if there are any other differences.

If you got an 04 STI, they use the 5x100 hubs (same as the WRX). 05+ use the 5 x 114.3 hubs.
Ah, I could see that being an issue.

http://www.youtube.com/watch?v=uN_jVWlSPmk

0:26 in & 1:17 in you can see the piece it looks like F5 will supply to connect the front knuckle to the upper control arm in place of the strut which seems to wrap around the knuckle and if the knuckle is indeed wider where it mounts to the strut, it looks like this piece would no longer fit.