I wouldn't want to contradict Strati, but my understanding is just the opposite. Arrow never made an S4-specific high pipe for the Monster. However, they made an S4-specific low pipe. I have Arrow CF high pipes on my S4. While I like the quality of the Arrow pipes, the brackets don't line up with the frame that well. According to Arrow, these pipes are intended to work with all years and versions of monsters. I believe that they were probably designed with the pre-2002 air-cooled bikes in mind.