Heh, yes, there were lots of loud exhaust options at the time .... Kerker was the brand used on Eddie Lawson reps. There was also Harris, and a lot of the Suzi GS riders had Alfa 41 (made by Micron, if I remember right). They were really short, literally ended at the pillion footrest.
My sister's boyfriend had a GSX1100 with an Alfa, and it was L O U D. He took me for a blast on it, and I remember looking at the speedo and seeing 130 on the clock. The noise was incredible.
They did versions which exited on the left as well as the right, here's a Kwak 650 with a left-exit pipe:
