Some peoples cars are fine with no trouble whereas others including mine have had expensive bills which the warranty didn't cover. Reasons for warranty to not pay out: 1 - Modifications, 2 - having had work done at an independent (none-audi) garage, 3 - failure to keep up exactly with the service schedule. When faced with a big bill Audi will find any excuse to not pay out. So no it's not a good idea but the risk is entirely your choice.