Whiteline rear sway bars are the same for all 02-07 sedans and wagons. Whiteline does, however, list different front sway bars specific to 02-07 wagons and 02-07 sedans. I think it's because the front end of the 02-07 wagons are slightly narrower than the 02-07 sedans (they have slightly narrower fenders as well). And now I'm actually thinking that I might have been better off with a Wagon front sway bar because if my front bar was slightly narrower, I would have that tiny bit of extra clearance between the Kartboy front endlink bolts and the Whiteline bar (see issue described below). I'll have to take a look the next time I'm under the car... that makes me wonder.
Regarding the fitment issue: On my 07 WRX, I was initially able to get the Kartboy front endlinks to fit with the Whiteline 24 mm front sway bar using spacers, but I didn't like the way everything fit. With and without spacers, the Kartboy endlink hardware was just too ridiculously close to the bar and I was afraid that the slightest sideways suspension shift would cause them to make contact, so I decided to reinstall my stock front endlinks. The stock front 02-07 endlinks are a very solid design (as opposed to the stock rear 02-07 endlinks which are plastic) and the slightest angle that they mount at combined with the fact that there aren't bolts protruding out of the back of them toward the bar provides more than enough clearance between the bar and links. I can easily adjust between either of the two sets of holes on the Whiteline 24 mm front bar using the stock front endlinks. Also, the way the front endlink bolts pivot makes them SO much easier to line up and get through the holes. I really had to wrestle with the Kartboy solid front links and the Whiteline bar to get the bolts through the holes when I was mocking everything up for the first time. If I were to use any other aftermarket front links, I would choose a design similar to the stock front endlinks - adjustable pillowball mount, as opposed to a solid mount. I had absolutely no fitment issues in the rear with my Perrin Stout Mounts, Whiteline 22 mm rear sway bar, and Kartboy rear endlinks. Adjusting between any of the 3 adjustment holes is a piece of cake.
Regarding the clunking issue: I heard a clunking issue from my front end after installing the Whiteline front sway bar and stock front endlinks, but I resolved the issue by tightening the front endlink bolts beyond the recommend torque specs. I definitely didn't have the bolts nearly tight enough the first time around and they were slowly working their way loose every time the car would go over a little bump in the road causing the endlink bolts to jiggle around the slightest bit in the sway bar holes. I also used a dab of blue threadlocker for good measure. I'm fairly confident that most of the clunking issues you hear about are because of loose endlink bolts. Crank on them a bit and the noise will probably disappear. Obviously, squeaking means the bushings need to be re-greased, so I'll see how that holds up over time and I'll report back if/when I have to re-grease any of my polyurethane bushings.
07 WRX (Albins 5MT + Blouch 20G)
Jorge Carrillo Tuned (365 whp/340 wtq)