As far as I know it's just stock gearing. I can get it to wind out to over 10.5K and into the 11's on a slight downhill, but it holds 65 all day on a flat. I drive that road everyday and know that the flow of traffic is always 65-80. I would keep up fine with traffic on the flat and pass some cars on downhills. The manual says it can do 70 stock.
I have no doubt in my mind that when your air leaks are fixed and it's nice and broken in, yours will have 75-80 pretty easily. Aswesome!