Hi Everyone. I have a 2003 Manual Accord Coupe and have the following installed:

AEM Cold Air Intake
DC Sports 4-2-1 Headers (Ceramic)
DC Sports Twin Canister Exhaust System

I installed the Cold Air Intake a while ago (almost a year ago) and it's been fine since. I then installed the Headers and Exhaust 2 weeks ago and noticed what sounds like a whistle noise when I excelerate. It only happens when I press the Gas and I'm in gear. If I'm in neutral and gas it, it doesn't make the noise. I took it to a Muffler professional and he listened to the system with his tools and said there were no leaks... I just wanted to know if anybody has ever many any alterations to their car and noticed something like this. My brother-in-law is a sports car enthusiest and he told me, "If you want performance you sometimes have to give up other luxuries." In this case there is now a whistle noise when accelerating. Other than that the exhaust sounds FANTASTIC. It has a very deep rumble and when you gas it sounds nice and deep. Thanks for your input.