ptgt - relax dude. John's observation was reasonable, whereas expecting someone to clear their thoughts/ideas/observations on a product with it's manufacturer before sharing them might be construed as unreasonable
They can't say it will attach to any downpipe unless they offer adapaters that mount between it and the various downpipes. A 3inch down-pipe will not fit a resonators 2.25 slip-fit otherwise, etc
They may very well have this sorted out, but nothing's realy wrong with someone raising the point that it might be an issue...