Yeah with 5 stud wishbones + 4 stud bearing carriers the wheel ends up further forward or back in the wheel arch, as the balljoint is offset different.
4 stud MK3 wishbones are fine to use though, but this will give you widetrack so track rods + shafts would also be needed. Passat 4 stud wishbones work too, but the roll bar may not fit though. It seems it depends who you ask! Was a recent argument about it on CGTI, Andy947 recons it fits and some other guys say it wont. I'd trust Andy as he knows his stuff, but I'm not going to say either way unless I have tried it myself. bIts a good upgrade if it does fit as the Passat bar is proper chunky
As a side note if you use Passat 5 stud wishbones you can use a 4 stud shape roll bar, so if you wanted 5 stud but already have an uprated eibach/h&r roll bar you can do it that way. Oh and if you want 5 stud narrow track, the early Passat VR6 used 4 stud bearing carrier with a 5 stud hub pressed in, and different 280mm discs to suit. Just need to fit 5 stud outer C/Vs to your old shafts.
