Mine was removed several years ago, it was not louder with the stock muffler. I now (3 months ago) have a Flowmaster 40, truck is slightly louder than stock. I had a full CAT back exhaust built by a local shop.
I too did an aftermarket exhaust from the outlet of the cat back in my 2006 Montero. The stock setup broke at the inlet joint of the original muffler (due to corrosion) so I removed it up to the cat. I think it has a flow master muffler without the stock resonator and it's loud. My wife and kids both hate going anywhere in this rig, I don't mind it, but it is much louder than stock.