I currently have two Magnaflow XL (stainless) mufflers on my car and they're... well.. pretty soft and quiet. I'm considering getting Flowmaster 40's... but only if the noise difference will be MUCH more noticable. I don't need opinions from people who own one or the other really.. but rather opinions from people who have heard the noise of the two mufflers and can provide an honest opinion over whether or not it is worth the expense and the time. If the difference is subtle, then I won't waste my time and cash. But if I'm going to be going "holy ****" because it's so much louder, then I'll invest $100 in getting two new mufflers and having them shipped... and lifting the car to weld some new ones on.