Seen it cheaper than that but yes does help
I put it into the rear well of my 75 tourer as I'd put a SS twin exhaust and was getting a bit of booming. Also put it onto the underside of the ZS saloon boot lid to reduce the 'tinny' feel of it.
Made a new timber base to the boot of the ZS and R25 and laid/stuck it on the underside. Superb result if I say so myself.