Im running a 24mm sedan sway in my 04 wagon with whiteline spherical endlinks and I just used a bunch of washers to make everything line up right, if that helps. Do your guesstimiations with the wheels on the ground or on ramps where the suspension will be static, this will be no problem because you have to have everything static to torque he bolts down anyways. Kartboy sells spacers for this. Home Depot/Lowes sells spacers, SAE though. You can bore out some of their nylon ones and probably be fine. I just get all my hardware from mcmaster.com so if you want the perfect spacer go there... But dude, washers are fine. Make it happen.
I did not know the 07's were different and would fit better, damned it- whats the difference in length/fit?
edit: haha I looked up my sway, its an 02-07 sedan/07 STi bar. Guess im in the clear. My rear is 04-07 STi, thats what I was thinking of when I was posting. I still had to use a few washers to make the front endlinks straight though.