The problem with the original silencers is they rot from the inside so once you see that they are generally shot. It is most likely that they will pretty much disintegrate when you chase for good metal to patch weld to.
There are some aftermarkets available but not many specifically for our twins. MAC in the USA make one but from my personal experience they are really crap quality. The one I got new was rusting after 2 days and needed the baffle welding back in within 2 weeks.
Marvin also did one. More expensive but much better quality. I think they don’t exist anymore but worth searching.
BSM in Holland made one. They have gone bust now but occasionally their systems do pop up on ebay.
So really for me there is no specific system I would go for. We have had Stainless Steel bespoke ones priced here in the UK which are in keeping with the looks of the bike for around £800.
Although I do like the sound from a 2 into one system (predator in mind) I think the bike really benefits aesthetically from a 2 into 2 system.