It might be of interest to note that dealerships make more profit on service, parts and warranty claims than they do selling new cars.
They want your service business. Dealers are not the manufacturer. They are independent businesses. They don't approve or deny warranty work. The factory does that.
Here's how it works.
Example #1. You bring your car in for service. You have a loose piece of trim on the interior. That's a warranty claim. The dealer fixes it. DC approves the claim and pays the dealer. Typical claim. No problem.
Example #2. You have 22" wheels on a car engineered for 18". Your front pads and rotors wear out after 19,000 miles of driving. Other owners with 18"s get 30,000 miles before repacement. This is non-warranty work. You are teed off because the pads and rotors are pricy. You demand a warranty claim. Because of the early wear, DC investigates. If they find out about the oversize, they probably will deny the claim.
Example #3. A front wheel bearing overheats and self-destructs, causing loss of control on the car. Or the rack and pinion steering fails. Both these examples are major safety issues because it's not supposed to happen. DC will investigate and if they find out about the oversize, they will almost certainly deny the claim.
Basically, any claims to do with brakes, suspension, steering transmission and drivetrain could be chalenged by DC. If your Service Manager, who works for the dealer, not DC, knows about your oversized wheels, he or she may not want to submit a claim, but charge you on the spot for such work. Each dealership has different levels of tolerance to aftermarket performance modifications. You may think the mod is just for looks, but oversizing will stress key running components.
Hope this helps to clarify this issue.