I would add about 3 or 4 MREs.  Some instant coffee, and a 12 volt coffee heater mug.  They are great!  

Plus a couple of folded up disposable or military style ponchos.    

I have used my jump start box and compressor to help a number of motorists and found that to be the best item I carry.  It is amazing how many breakdowns along the road are folks with dead batteries!  And when you need a jump nothing else will do except a good samaritan with cables or a jump box!

A good first aid kit with a major wound type dressing could be a life saver.   Add a CPR mask.  And a multi tool or multi knife.  

Oh yea a good portable light too.