Max, it's possible, if they used a VW transaxle with a Subie, that they subbed out a Weddle gear for the stock VW 4th. (And this is only a guess, at best).
While not straight-cut gears, Weddle gears are designed for competition use and are a little closer to 'straight-cut' than stock. At any rate, they do whine more than stock and have a distinctive sound.
Two Weddle gears were used in my five-speed, and they definitely sound different, and louder, than the other gears.