I got flow's on my car, and I love the sound now. I am a firm believe that flow's have to be "broken in" I dont know if they are 40 series, but I know they are dual chamber'ed if that means anything confused -Nick

"My family hauler can kick your family hauler's @SS!"
~~~~1999 Contour SE Sport~~~~
-KKM True Rev
-Custom cat back Flowmaster exhaust
-All Cat's fixed.
-SHO Shop Off-Road Y-pipe
-Many other Mod's done...