First off, I went with this same wheel/spec and after almost 1 year, I love them. Here's a post I made with pics...let me know if you have any questions about my wheels/setup.
http://www.ft86club.com/forums/showp...2&postcount=15
As to the question of the dealer making issues...I don't know for sure, but I would doubt it. If you've already brought the issue to their attention, I would go ahead and ask them if new wheels would be an issue. Wondering if your rear wheels have been re-balanced to see if that affects the vibration?