You're the wet dream of every bike thief on the planet. Wire cutters small enough to fit in a pocket will cut through that cable in a couple of seconds. Get good U locks ($50-150) that lock both sides of the shackle and have 12-13mm thick shackles, and secure each bike with more than one lock, every time. My most expensive bike cost half of yours, and I have Pit Lock skewers, security bolts in my saddle clamp and seatpost clamp (nice seatpost and Brooks saddle), and an Abus Granit Plus 640 U lock (the lightest with the thickest shackle). I don't have security bolts in my stem (the ones with the little pin in the middle of the hex heads—take a special hex key to turn) because I have a quill stem and they don't make them that long. Most thieves wouldn't go to the trouble to take a quill that would then have to have the bars unwrapped to sell to someone with a threadless stem. Also make sure your bikes are covered under your homeowners insurance. It will probably require getting a rider to your policy, but worth it for expensive bikes.