My car is not going to be raced so my HP is not so important - I like the sound of chambered - would you say mac is a better muffler ?
As far as sound goes, the sound of the chambered muffler over powers any intermediary as well. Most of us old guy had chambered mufflers when we were younger. This is a matter of learned experience. That chambered muffler will absolutely drive you insane within a year or two. Those bitches have this constant drone between 1800 and 2400rpm, like right where the engine is at highway speed. You'll be going down the highway on a long drive, and that drone will eat into your subconscious. I think Flowmaster mufflers are the incipient stage of 1 out of 3 serial killers.
Kurt