Talked to the rep at HAN about these. They are very slim(4 ") and can be place anywhere. Also, they have a heat barrier in the casing which makes them a good application between our gas tanks and springs.
There are several sound files in the link below, probably not 6's though but you can get the general idea. Javascript must be enabled!
http://www.flowmastermufflers.com/cgi-b ... d=QfDsb5v6