update: removed the restrictor out of the kaki regu today, definately is louder, havent driven at WOT yet as i wanna get it on a dyno to make sure its all good first
took some pics on the way incase someone is thinking of doing the same, took about 2hrs all up from removing the exhaust to re-fitting it, used a dremel to cut it out, the restrictor as mentioned is 2.5" and roughly 20cm long
pic of the restrictor inside
restrictor cut
restrictor removed
restrictor next to zorst
http://s234.photobucket.com/albums/ee47/bwrgtr/?action=view¤t=748ba40c.mp4
quick vid of the exhaust note, its got more growl in low revs, havent tested high revs yet