This is a combination of experience, equipment, savvy and Kentucky windage. We are confronted with different parameters depending on the application. For example, we make a significant number of OE and Private Label systems, and each manufacturer has different criteria: Ford Racing may want an aggressive Mustang system while Steeda may be looking for a more subdued sound or visa versa. In the systems we make for the various aftermarket arenas, our customers participate in the design process. We are also governed by federal and state regulations regarding emissions and sound. Fortunately, thanks to SEMA, we now have (in most states, including California) a db number for sound which is 95db. We use the SAE J1492 (replaced SAE J1169) testing procedure. Borla is most well known for making a very mellow growl rather than a painful bark. We do this while providing a gain in power and performance due to the technology of our entire system.