I have a Magnaflow SI/DO with a Magnaflow high flow cat. I love the sound of mine. The first clip in that thread is my old set up. A SI/SO Cherry Bomb.The magic words that you said were "semi-quiet at idle, with hearty noise at acceleration". I would recommend a Magnaflow system first, then maybe the Flowmaster 70 or 50 series Delta Flow. I personally like the Magnaflow muffler for its quietness and performance, the Flowmasters are generally louder.