I too have felt the buzz..
On a trip to Albany from Perth I got a chipped/cracked screen. I had heard it could be a problematic fix so I took it to the main dealer south of the river where I'd had all my services since new. As it is an HSE with auto lights, and wipers etc I didn't want an after market replacemenet. I was assured that they would take care of it and they only use a firm from north of the river who they trusted and did all their work. $1300:00 later I picked it up and within a couple of days noticed the buzz.. it kicked in when I reached 100kms or close on a gusty day. Close examination revealled a gap at the top of the pillar covers, both sides. Phoned them up and arranged for the service manager to have a look to see what the problem was. He examined the pillar covers and said they were broken and asked if I had had the windscreen replaced recently, and offered to glue them in place for me. I said they had replaced the screen and I wanted them to replace the broken parts. He checked their parts and said they only had one cover in stock and would call me when they had them in. After a month I figured they'd had enough time to get the parts in and chased them up. The service reception lady said the hold up was because they were trying to contact my insurance company to claim the cost from them. I thought that was strange and told them so as I had paid them for the repair. I asked them who I was insured with as my broker delt with the claim and didn't really know who it was. She said she would get back to me. Couple of more weeks and I was told that the main manager had said they would pay for one if I paid for the other. How much are they I asked? $160 each side. "That would be retail price, right? Regardless, you broke them while the car was under your charge, you have to replace them". Eventually they conceeded and replaced them. This immediately stopped the buzz, it was so good to have a quiet car again. Three weeks later I got an email and text letting me know my car was due for a service and asking if I would like to book it in. I have had my car since new, picked it up in Jan 2011, done 160k, it's probably ready for all the major services, nearest off road it's done is crossing the mediun strip. It won't be ever be serviced in Cannington again while I own it.