The first step is to figure out what you're trying to do with your bug. Do you just want a simple audio bug? Do you need a video feed as well? Do you just need to locate the car with GPS? Once you have this in mind, you can start to get a better picture of where the bug will be placed. For instance, a GSM-001 is a pretty common audio bug that can be placed under dashboards or practically anywhere with a 12V power supply.