Im a senior in mechanical engineering and i get most of what you are saying but im having trouble applying to what i should do for my ride.
Looking at my stock exhuast i was wondering why it goes from about 2" to 1.5" near the muffler, but now i see thats their to maintain the exhaust gas velocity.
but what im trying to figure out is what my best option for modifying my exhaust to get better performance. I bought some "DC style" headers and a high flow cat, and that seemed to decrease low end torque a lil and maybe help high end a lil.
now im trying to figure out what to do about a catback, cost is a big concern for me being in school and all, so i could get a 2.25" catback for under $300, but im wondering if this will even benefit my performance much? what should i do?