Hi, I want to install a new exhaust system from Magnaflow or Flowmaster at my 72ger Oldsmobile 442 (455cui). I’m thinking if I’m not installing new fan manifolds right away, because that’s supposed to bring even more power. . . My questions: 1. How much more power would such an exhaust system bring and how much more with fan manifolds? (approximately) 2. Will the car with the exhaust system and fan manifolds not be too loud? (…not that the police are holding me at every intersection? t) 3. How about the registration of AMI-parts with vintage cars? 4.How good or bad is that for the engine? 5. What experiences have you had…?