Which Magnaflow?
#18
My Magnaflow 11"s are about equal with Flowmaster 40 series with all stock cats. But its not as loud as a 2 chamber at idle, but they sound better than Flowmasters.
#20
Yes. Not quite as loud as mine due to mine is dualed, and I removed my rear converters, but after it breaks in it would sound quite nice. You'll be up there with the 2 chamber mufflers in decible levels, and it will have that rich, deep, clear Magnaflow sound
#22