I can say that asking this question is like going to a burger shack and asking people what kinda soda should you drink. Everyone here is going to have a different opinion. Dont forget the search feature as this topic is covered several times.
But here goes..... I used Champion Truck plugs for a while... also used Splitfires (wont ever do that again), Bosch, Autolite, Denso/NGK's, etc..
Platium plugs are good for longevity. The platium is harder then materials used in regular plugs and also does not take as much engery to transfer electrons. They run more efficiently for a longer period of time. Also when they reach operating temps they are self cleaning. Now there are those that are totally against using anything but Champions, or AC Delco, or Autolite, and they will never listen to anything positive about using a Bocshe, NGK, etc. And in some circles you will only hear one or two different brand names mentioned as if they are the Gods of the Realm. Im most Volkswagen Aircooled you only use Bosch, or Toyota guys only use Denso or NGK, and Some 4x4 groups that run mostly domestic rigs only use a namebrand accociated with US 4x4's.
I have used Bosch platium plugs and they work very well. I have had issues with Champion plugs at times and when my last rig would not pass smog testing with brand new Champion Truck plugs I replaced them with a set of Denso regular plugs and it passed with flying colors. With the Bosch Platium 2 plugs you wont need to gap them and they have twice the platium. I do not think you need to use the +4's as I really do not think you will notice anything. Its just overkill for the stock motor. Ive seen a couple threads that brought up the use of NGK Iridium plugs... Iridium is 6 times harder then platium and has a higher melting point. It transfers electrons even better then platium. It is very expensive as is platium. So not all platium plugs are made equally. Bosch and Denso/NGK platiums are very good plugs and I do not think you can go wrong with either. The NGK Iridium plugs are even more awesome but they are like 3 to 4 times the cost. Some of my friends run them in their cars, all of which are either running a turbo or SC engine. I thought about buying some for the XJ but it just to much money for me to justify spending.
Caps and Rotors..... make sure you get a good quality set... with brass or even copper inserts... if they use aluminum they are cheap. Aluminum also oxidizes more then brass or copper and is very harsh on the distributors bearings.
I like to use a good quality plur wire set... Bosch is one of my favorites unless I dont care much for the vehicle at the time and then I buy a good brand that doesnt cost as much as the Bosch wires.
Also dont forget about looking into the O2 sensors at this mileage and maybe the coil.
