I bought my Sil-Moto system secondhand so I don't know exactly what it is.
I've only ever seen one other like it.
It came from America and had clearly been crashed as it was quite damaged when I got it.
It was cheap though and the basic design was almost exactly what I was after so I took a punt on being able to repair it.
It needed a section cutting out and replacing from the front header which was seriously scraped and half flattened.
I would have had to cut the front header to shorten it to fit the 750 anyway, so it wasn't so bad.
And yes, the headers are overkill (probably) at 50mm bore although I didn't realise this at time of purchase. And the whole thing is 1mm wall thickness (I think the std headers on my 750 were 1.5mm wall) and its extremely light..
The tube is actually the same size spec as the std hi-level link pipes from an S4R. I know this because the replacement section that I used was taken from a link pipe given to me by Capo which came from the original system on his bike.
I measured the length of the headers and was pleased to find that they are both the same length.
I don't do photos much but there's a pic on post #4 on this thread from the 2019 weekender.
http://ukmonster.co.uk/monster/showthread.php?t=57395
I didn't notice any particular gain or loss in performance after fitting the Sil system but I must admit that I did nothing to tweek the fuelling so I may not be getting the best from it.
In my defence this was because I had a pair of Kehin flatslides to go on and I was waiting until they were fitted before heading to a dyno.
Then covid and life got in the way and the Kehins are still waiting (yes I know ... shame on me).
But it does seem to run ok as it is.