After changing belts on my 90 535 in the chevron parking lot with just the BMW tools and a crescent wrench I need to put a small but quality tool kit in each car's trunk.
I was thinking about a 3/8 socket set with extensions, good end wrenches, screwdrivers, torx, pliers, side cutters, knife, and a small bar.
Duct tape, spare belts, spare hoses, hose clamps, oils, and water should cover.
Any other suggestions?
I keep a few tools in my car, roughly the same you have listed. I have them stored in the little area in front of the spare tire...lift up the carpet there is a wide channel there that's perfect for this stuff. I had some sound deadening in there to keep the tools from sliding around.