Be real careful and read all the paperwork with this one. BMW doesn’t normally CPO a tuned car. Even with the normal factory warranty, BMW will not honor a tune related issue, Dinan or otherwise. In this case, Dinan is supposed to foot the bill. However, the supplementary Dinan Warranty only applies to the original factory warranty of 4 yrs and 50k miles. To me, all of these throw red flags and I think the dealer is just trying to upsell a warranty on bad faith.