I just noticed, on the TYGA website a similar adapter is available - http://tyga-performance.com/site/product_info.php?cPath=72_79_112&products_id=957 allowing you to mount tiger silencers to any pipe. However these require welding so I thought I'd better mention that the ones I have are aluminium spacers that bolt on to the stock pipe as well as the silencers. Eliminating the need to cut and weld the pipes.

So they'd be good for somebody who doesn't want to cut their pipes and weld a new piece on.