They were very common in the late 80's, I ran one on my Tecate w/ my PSI pipe. Now I would say they are rare, cuz most were trashed or wore out many moons ago. They were on equal ground as FMF or DG.
"If you are going to piss like puppy, Don't Get Off The Porch"
Trikes:
84' Suzuki ALT185 (old Orange)
85' Yamaha 225DX, piped and spaced ( First Girlfriend)
Quads
87' Yamaha Banshee, built and very very fast (The Whore)
01 Yamaha Raptor 660, built and piped (The Beast)
03 Suzuki Vinson, 26's and piped (The Crowd Pleaser)
Once apon a time:
85' Tecate 300 alky flattacker, 6 in over swingarm, 88 Suzuki 500"Quadzilla"PIA , 91 Yamaha Warrior Built and Modded. (luved that Baby Tank)