My Lanfanconis were just expansion pipes.
They were so loud (103 dDBA)I tried packing them with wire wool and eventually bought stainless exhausts to cull them to 90 dBA.
Mind you my 1974 T140 V Bonnie made 107 dBA and the Dutch authorities passed on import it as the test centre lads were all HD riders!
The trick is to be ahead of the sond wave i.e. drive forwards & grin!
