As we dive deeper in to the research for our JK project vehicle, we are finding a few issues that may keep us from building it "right". One of these issues is the lack of a solution for calibration of the vehicle speedometer. The new Wrangler uses a CAN Bus system that pulls data from several sources for the electronic speedometer, rendering a simple solution like an adjustible potentiometer (think Superlift TruSpeed) not an option. Of course by now you are yelling at us, "Gears you dummy!" That sounds like a great solution until you realize the JK aftermarket only has 4.88s or 5.13s available and with the revvy nature of the new 3.8L, 4.88s make sense for our 35s (although, 4.56s would get us close to stock), especially since we have the six-speed manual. This gives a little more low power down low, but we have enough gear up top so mileage won't suffer too bad. and it should make up for heavier items like bumpers, winch and tires. That being said, we would be almost 10-percent off if we didn't do gears, and swapping to 4.88s and using 35s we would still be quite a bit off. What's a magazine guy to do? Well for now we have some e-mails in to Jeep engineers to see if there is a solution. We'll also keep scouring the aftermarket for to see if anyone else has answers.