No1 you ALWAYS replace wish bones in pairs as you said youve only replaced one these are the main problem with mk5s ,cant seeing it being the driveshafts as this wouldnt really make it swerve all over the road,just you may get a knocking sound when on lock to lock on bumps(that would indicate that the cv joints are fooked),just check ya track rod ends and front springs as they maybe broken (CHECK THOROUGHLY)! let me know how you get on!