The Proflash programmer plugs into the computer port on the left side lower dash area/driver's side. The programmer allows you to select different fuel octanes, shift points and ratios for economy, towing or performance driving, timing settings and general performance settings. You can set the computer to be more fuel efficient or provide more torque and horsepower. My intial impressions are very good. I notice firmer shifting, increased throttle response, and improved overall performance. I pull a 30ft. SUT trailer and needed more torque than the vortec was providing. I am anxious to test the upgrade when I pull the trailer once our weather warms up and I can get out my bikes. The unit cost is around 400.00 and is very easy to use. The programmer saves all the stock info and you can reload it any time you need to return your H2 to your dealer for service. It takes about 5 minutes to do the install once you are familiar with the procedure. I am more pleased with the results every day. If you have any more questions you can e-mail me directly at
jayh@mobile-e-service.com. I do not sell this unit, I am just a satisfied customer and feel that H2 owners could benefit from this simple to install system. Jay