I agree the stocker does sound like a sewing machine. Have you looked at Jardines or, Heaven forbid, PREDATORS??? If you would not mind some performance increase in addition to noise increase those are two fine choices. The PREDATORS would be custom, of course, made one at a time by TravelGuy.
Of course if you also did the triple K&N filter conversion, which costs just a little over $100 if you do it yourself, as I - with my eleven thumbs - did, using MiamiDave's incredibly detailed and illustrated step by step how-to ), that might just add a few ponies and will definitely add some queer noises to your machine. That mod meshes extremely well with either and both of those exhaust mods above.
cheers