Put my new fob together today. The hardest part as 180 already mentions was getting the original apart. Damn they glued them up tight! I'm thinking next time using a Dremel tool to cut the shell apart at the seams. That said, assembly is pretty easy. Swapping over the parts includes the plastic retainer that holds the transponder in place. Make sure you are working in a "secured" area so when things drop, you don't loose them. The transponder is very small and easily lost. The only issue I had that took a bit of time was the ignition key itself. It is spring loaded and the instructions are pretty clear, which includes two counter-clockwise winds to tighten up the spring. The plastic button release is pretty obvious as to how is mounts, however I ran into difficulty having the key "latch" when fully assembled. In other words, have it stay closed until the button releases it. I don't know what I was doing wrong, but it took three tries (closing the shell and re-opening it) before it would latch properly. It's all complete and the Crossfire will need re-programming, but I can't do any of that, including testing the fob as the car is in storage, covered with the battery removed. I think I'll wait to confirm that it works properly before I get into the second fob and do the same...