Over the past 15 years, I've gotten countless inquiries as to whether or not upgrading your BMWs audio system will interfere with your factory (or aftermarket) vehicle warranty. These days, we know that the majority of new BMW's are being leased, and there is an unfounded fear out there that people seem to have with regards to making any changes to a leased vehicle. Well, the question begs; Does adding or upgrading my audio system compromise my warranty or invalidate my lease? The short answer is no, upgrading your speakers or adding an iPod or a subwoofer to your system will not interfere with your vehicle's warranty. The long answer, which again is no,  is covered in the Magnuson Moss Warranty Act of 1975, which can be seen here: http://en.wikipedia.org/wiki/Magnuson-Moss_Warranty_Act The speakers aren't in any way tied to any components in the vehicle outside of the factory amplifier. They actually present less of load to the factory amplifier in most cases, as we've made them more efficient, thus allowing the amplifier to not work as hard. Adding a subwoofer does of course rely on your vehicle's battery for it's power supply, but provided you don't listen to the system with the car turned off for extended periods of time the car will be none the wiser to the woofer being installed. Beyond the battery, the subwoofer is otherwise removed from any of the vehicles specific components. Now, if you're smart, and you likely are as you already own a BMW, you'd remove the equipment before trading your car in or turning your lease back in. Just make sure to keep your factory equipment stored in the garage and reinstall it before you head out to the dealer. Easy enough! If you have questions beyond what's covered above,  drop us a line at info@bavsound.com or give us a ring at 404-963-8857.