i personally self made mine, paddocks sell a 'sports exhaust' which is a rear section and a pipe instead of a middle silencer, 35 quid not bad. i used a decat pipe too, 20 quid.
i chopped off the rear silencer before the final bend, and used a 45 degree angle section of pipe cut from the old rear section. that slotted straight inside the bigger diameter new exhasut, and gave the correct angle to go straight out the side of the rear quarter. then i welded on a shiny tip, but thats not essential.
i hope... that is of help.