Originally Posted by F.I. Inc.

Everyone I've ever encountered has always run the headers with an aftermarket exhaust system. From a performance standpoint, it does not make sense to run the headers with a stock exhaust system. The bottom line is, the stock exhaust system is too restrictive to run with our headers. To answer both of your questions, we do not have, nor do we have plans to, dyno test the car in that configuration.

If either one of you have any further questions, please do not hesitate to call me.

Thank you,
Tony