Throttle response/sensitivity preferences vary wildly from one person to another. While others (Dinan, BMW, etc.) may think their throttle curves integrated into their software offerings are perfect, you may not feel the same. Don't settle, take matters into your own hands and design your own custom throttle curve catered to your personal needs and desires with the Dinan Throttle Booster! Equipped with 5 preset throttle curves for easy adjustment from the wireless control switch (or app) you can quickly select a throttle mapping option that works for you. If those aren't ideal though, you also have thousands of potential curves you can build yourself in the associated iOS/Android app. Save up to 3 of those customizable curves directly onto the device and throttle options for numerous and varied situations are at your fingertips instantly. Best of all, the Dinan Throttle Booster installs in minutes and is fully reversible. A richer, more enjoyable driving experience has never been easier to attain! E38/E39/E46/E53 FITMENT: See note under "Tech Resources" below for important information to consider before installing.