* The specific wording of your warranty: Carefully read your warranty document. It likely contains clauses about modifications that could affect the powertrain. Look for language about alterations to the emission system or anything impacting engine performance.
* The cause of a powertrain failure: If your engine or transmission fails, and GM can prove the modification directly contributed to the failure (e.g., a poorly installed exhaust caused a fire that damaged the engine), they may deny warranty coverage.
* GM's interpretation: Ultimately, it's up to GM to decide whether the modification is related to the failure. They have considerable leeway in these situations. A technician might argue that the increased back pressure (or lack thereof) from the aftermarket exhaust stressed a component, leading to failure.
In short: While a dual exhaust or a Flowmaster Super 40 isn't guaranteed to void your warranty, it significantly increases the risk. If you're concerned about maintaining your warranty, it's best to discuss exhaust modifications with your dealership *before* making changes. They may have recommendations or specific guidelines. Keep all receipts for parts and installation as well.
If a problem arises, be prepared to argue that the modification was not the direct cause of the failure. Having good documentation could strengthen your case.
