I hear a strange noise (with the windows up) coming from the engine. It starts in any gear at 3000 RPM and up. Sounds like a roar/exhaust/glasspak type of sound. Hard for me to describe. It is loud and I never had it before. I have added JDM chip,90 mm Pro M,oil breather,NGK 5's,"monster" box tranny on my 1999 L. Anyone have an idea? I do not race and hard use is rare. Any help will be greatly appreciated.