I ahave been reseraching security systems and considered the Ravelco security device. I had read many scare stories about how car thieves use decoders to bypass factory security systems. I had a car stolen in front of my house and don't want it to happen to my new Challenger!

In another forum, a similar issue was discussed. Lucky for us, it seems like Daimler-Chrysler has the best factory system on the market and there may be no need for a supplemental security system. (Note: GM's "Pass-Key" is one of the worst).

Here is a quote from the site explaining how the DCX system works:

The security module queries for the code. And its not the same code every time. That chip actually generates a new code every time. The security module knows the math formula that the key chip uses, and so it can tell its a good one. Meaning that its one of the keys that it "recognizes.

The security module solves a math problem, using the code and some other stuff, the VIN is a part of it, solves it, sends the raw data off to the engine computer, which does all this over again, and sends its answers back to the security module. Which then compares its answers to the PCMs, and if anything does not match, your done, shut down. You get three tires, if that third one fails, it takes a Starscan and a call to DCX for a code to reset the system.

For you geeks, its a 32 bit PKI style system, made by TI. Ford runs the same basic system, but only the security module does the check, then sends a simple signal to the engine computer, which can be faked.