[Creeper]

If you want to be seen LED tail lights are an option as for headlights you can try making a set of LED's or getting a set of Halo light real halogen not the white lights all be it that if you do not have projector housings you blast the light everywhere and while people do see you they can't see with the lights. Avoide a roll cage which can be used for a 4point harness unless you use the car for racing a Import Tunning did a studie on this a few years back and a roll cage with 4-5 point harness could kill you in a crash as it will be a difficult to get oiut of the car once in a crash and if its on fire as well as knocking you into solid steel tubing might break a few bones.

You could upgrade your brake system to large brakes with bigger calipers and an upgraded pump system to supply the proper break pressuer to the calipers you would also need to upgrade the lines to braided lines to handle the pressure. Slotted rotters would help with distributing the heat of the braks cross drilled are prone to cracks. I know a read tires are big as well good tires with decent to allot of grip will help you stop.

If you get stuck on the side of the road with a flat and its a highway try limping the car to a spot where you can get out safly i.e. where there is no gaurd rail only you and a grass median would be safer. Yo would chew your tire but it would be safer then the alternative. Keep a sup[ply of road flares and a repar reflecters along with your hazards on so you do not get hit. Thats mostly how I would emprove a vehicles safty.