[GTvert]

I have a 01 gt convertible, and a hypertech programmer.
Since there is no speedo gear to change in the newer transmissions, There are only 2 choices if you get gears.
1)buy a speedo recalibration box (like $100)
2)get a programmer, and pick up some extra horsepower plus have the option change rev limiter,top speed,etc.
You can notice a difference when you program your car immediately.I was actually surprised.only takes like 20 mins to program it.I have an x-pipe, cold air induction,steeda underdrives, and a few other things and can tell nothing wrong with streetability, idles and runs great.I paid close to $300 for mine, but I would do it again.Hope this helps.