Spare engine, rescue helicopter, NASCAR pit crew, Wingman in F18 Superhornet, Uhmm.... Sorry, I know, not helpful. If you put everything in your kit that we all recommend, I'm not sure we meet the 'Not too heavy or extensive' requirement.Lynn, That was great but she is right you can only carry so much stuff. I do my own wrenching. The extra parts I carry are my pull offs I save my old plugs, wires, hoses and belts there good enough to get me out of a tough spot. Your tool kit looks pretty good. Most newer cars need a 1/2 inch breaker bar to change the serpent belt. Do all screwdrivers are pretty good but still like to have a good med flat tip and #2 Philip screw drivers Crafsman or better I carry Snap-On. If you have room some oil, transmission fluid, fix a flat and brake-fluid. I carry a head lamp and my back up is a 3D Maglight it all so doubles as a war club if need be. ;-)
Also a good quality socket to fit the wheel nuts/bolts, with a long extension bar to suit, so that you can undo any really tight wheel nuts. I also like to check that the jack will raise a wheel enough to change it with a fully pumped up tyre (not always the case in some vehicles).