Ok so this is where I'm at with my research. The upgrade from 17inch to 19inch is not the problem as the rolling diametre is identical. The problem lies in the load rating, KXR wheel placard states no less than 107, while the Alttitude, KXS and Grande states load raing to be no less than 103. Toyota: Called Toyota and their only response is 'we dont recommend modifications to the vehicle and you should keep it to factory spec'. This is what pisses me off, they are happy to charge $2,500 as a factory upgrade at the time of purchase and also change the factory wheel placard to 19inch wheels, but to source the wheels yourself for for less than half that price they aren't willing to give you their approval, nice. Insurer: You are allowed to upgrade wheels as long as it complies with the law. This is my major concern as the load rating on the KXR placard is 107 and the Alttitude, KXS & Grande have load ratings of 103. Local Car Engineer: Any factory option is legal. Doesn't matter what is stated on placard its only a sticker. RTA: Spoke to a technical officer at the NSW Roads & Maritime and he could not understand why there is a difference between the KXR and other models. He also acknowledges they are identical vehicles. He done some research on the compliance of the vehicle and tells me the KXR is complied with tyre rating of no less than 107. But he did say one last comment which made me think, he said check the specs in the hand book and what ever the factory recommends should be legal. So I opened the hand book and in the wheel specifications it mentions both wheel sizes. 245/65/17 107S & 245/55/19 103S, but no where does it say for which particular model the size applies too? So would you take the handbook specs to mean you can use either of the two sizes dosent matter which model it is for? Pretty confusing stuff and also very critical in ensuring you are covered for insurance purposes. Any thoughts??