Hi all, I'm posting this on here as a first time poster on the off-chance it might help someone else in the future. I've relied on posts and how-to videos from here in the past so I'm trying to do my bit. Recently I had new tyres fitted to my VZ Calais and only a week or so later a mate replaced the z-bar bushes for me. Not sure when exactly it started but within the next day or so a bad out-of-balance type wobble started with it being the worst at between 55 and 65 km/h. Noticeable at other speeds but really bad when sitting on 60. I went back to my mate and we re-balanced all four wheels, did another wheel alignment and the problem persisted. I took the car back to where I purchased the tyres thinking it could be a tyre fault (even though they looked perfect on the balancer) and they rebalanced them and still the problem persisted. Hmmmm. I was buggered if I could figure it out so I took it back to my mates this morning to hoist it up and have a good look underneath at all suspension parts, brake parts, steering rack etc to see if I could figure it out. I was starting to think it may have been a bent tail shaft, a dud uni joint etc when, while turning a rear wheel to spin the tailshaft I spotted something! One of the three bolts that holds the tailshaft onto the coupling coming from the transmission was missing. No idea how it could have fallen out, the other two were t.a.f but I was pretty confident I'd found the problem. I didn't have a matching torx bolt so I put a hex bolt in and took it out for a spin. FIXED!!! No matter what Google searches I did for this problem nothing seemed to point to the tailshaft and I'm sure that without a hoist I would never have discovered it. I'm adding a few tags to this post to possibly help anyone who has this problem in the future.