Hi,
Not answering your last question...
But the lad in the link may have made his pipes louder, but it isn't coring in the true meening of the word!
To do the job properly and get a performance gain, you need to remove all of the mechanical baffles (everything between the 2 end caps) then weld in a straight through perforated tube of either 45 or 50mm ID, wrap this in silencer packing, weld a length of flat plate along the full length of the inside of the can to line up with the holes in your outer sleave and drill it to match up with these holes.
Now either weld on some 8mm nuts or fit threaded inserts, to accept the original hanger bracket bolts.
Put the whole lot back together and use stainless pop rivets ...
You'll now have a pair of cans that will work and sound as good as a pair Termi's, as long as you alter the feuling to suit by either 'chipping' or 'Re-jetting'.
Also they'll look the same as standard pipes unless you look up the ends.
Which should keep the MOT man and the Police happy.
Steve