Is there a bung I can get to put in the exhaust, its a turbo model, will I just need to put a bung in 1 of the back boxes or both of them. They're aftermarket back boxes about 3 or 4" dia i'd guess, where do I start to look for a bung for these?

Edit: Ok, I found a baffle bolt in type bung. Will I need to fit 1 in each tailpipe? Also, if i stick some steel wool in behind the bung will this help reduce the emissions in any way and how will I get the steel wool back out afterwards, will it come out with the bung removed under the pressure of the exhaust itself?
www.ebay.ie/itm/Stainless-insert-Bung-Ex...?hash=item1e68590e5c

i got a bung/silencer & put steel woll around the inside of it (or a scotch pad)
held on with a dublee clip...
it will reduce noise but not emissions

If you have a twin exhaust system just get a blank to cover up one exhaust completely and use that silencer in the other exhaust with steel wool, once removed the steel wool will fly out from exhaust pressure.

also to add
literally pull up & put the wool & silencer in about mile or less from the test centre as its not good to have the exhaust backed up

andy t wrote:
also to add
literally pull up & put the wool & silencer in about mile or less from the test centre as its not good to have the exhaust backed up

Makes no difference you can leave it in and drive around like that if you want you will just be down on power.