Additional trunk lights are cheap but well worth it. Dashcams front and back (in one accident so far, the dashcam footage made proving fault trivial, saving more than the cost of dashcams for both our Teslas - reinstalled the dashcam on day 2 of ownership of the replacement). In out case Blackvue, but there are other options out there. Something which may or may not appeal to you, front and rear radar detector (tells you direction of radar) plus laser jamming system (jams police laser while warning you until you slow down) - in my case Stinger VIP but as with dashcams, there are options.