Thats probably the same guy who sells the +20 hp "performance chip" on ebay. Look up "Can Bus" on google, and you'll see its just a "wee tiny bit" more involved then that.
There is a solution for the Mazda 6 that removes the governer...but it costs about 700 USD and is sold by unichip. So far nobody has done it...cause quite frankly, nobody but street racers cares, and the street racers aren't willing to spend 700 dollars to go 10-15 mph faster.
You won't hit 120 mph on the strip, nor will you hit on the track (unless its got a mile+ straight).