i dont know about the quality/performance of their motorcycle exhausts BUT S+S exhausts on air cooled vw's is top notch stuff. i had an s+s dual aluminum silencer system on a 210hp dual carbed 2500cc bug motor.
After checking around to try to find out more about S&S, I emailed the company and they replied with this...
"We sold the S&S motorcycle line to Jardine Headers about 1980 & he sold out to Inter Am. The only bike headers we make now are Private Label for other companies. We also make Mini-Sprint headers for Circle Track Cars with bike engines."
So, there you have it...
I have heard of Jardine but not Inter Am. I don't know that Jardine's reputation for quality was/is stellar, but maybe somebody else could comment on that...