The easiest to play around with would probably be American cars. Around 2003 GM and Chrysler started introducing CAN controled door locks. I'm still waiting on my carloop but once I get it, I'll post what I got working on my Buick. Japanese cars are less likely to have CAN connected locks. Any vehicle can be interfaced with using relays triggered by an output of the Electron. To find out if your vehicle uses CAN to lock and unlock you would need to log or monitor the CAN data while using the locks. Try pressing the unlock button on the driver and passenger doors, try pressing unlock from the keyless transmitter, and try turning the key in the driver and passenger door cylinders. Some, all, or none of these will produce a reusable CAN message for unlock depending on the vehicle.