With a 6# pulley and an electric fan I pulled 450hp and 560tq out of the engine ( 385rwhp/ 480rwtq ). Thats PLENTY for a daily driver ... I keep up with a lot of stock muscle cars on the streets.
My friend had the Magnaflow exhaust and it didnt sound much different than a stock exhaust IMO ... a little quieter at idle but a little louder at WOT. ---