Many people are not familiar with what a Valvetronic exhaust is or does. The idea of at the push of a button you can switch between quiet and racing mode is a feature which Cloudsale has on many exhaust systems. Where other exhausts are always loud but this Power valved systems allow you to switch to a quiet mode. This Normal quiet mode is usually the same as a stock unit by restricting the exhaust flow. With the exhaust valves open, the system roars giving you the performance and sound you desire. Cloudsale also provides these valvetronic exhausts for the BMW M5/M6 V10, Nissan GTR, and the other high end cars.