Wizzy, you are right, I work as a service advisor for a Hyundai dealership & have for the past 10yrs. We will repair any claim under warranty, unless its due to an accident, lack of maintainance, improper maintainance, or a modifiaction that has directly resulted in the failure.

Your are also correct in that interpretation is different from dealership to dealership & if you get a prick for a service advisor or service manager, the chance of it being covered is less likely. I would not say our dealership is tuner friendly, but we are not bias one way or the other. Just keep in mind modifications car have consequences, I know this already & I'm still going to modify the bejesus out of my GenCoupe & deal with consequences if there are any.
Final note, adding a dealership review section is an excellent idea. I feel I do a pretty good job, but alot of customers complain of other dealerships not too far away. I wish it was not so, but hopefully that will change in time, especially if they see that dealership personel is Hyundai's weak link.