Faraday pouch is probably a good idea-- the latest Ford key fobs have a motion sensor that will turn them off after 40 seconds of no motion, so they don't respond to relay attacks. But, of course, thieves are smart and always outsmarting defenses. Because so many parts of newer cars have micro-controllers, those vehicles basically have a built-in local area network for communication between components. There have been some thefts of newer cars where thieves break a headlight and use the connection to hack into the network to unlock the doors and turn on the ignition.
Security reminds me of surviving a bear attack- You don't have to be faster than the bear, just faster than the guy running beside you! If your car is harder to steal, thieves will move on to an easier target.