As far as tune up, try and get cap and rotor with brass terminals. Stanard is a good brand. There are others. Spark plugs for a Jeep, Most say NGK or Champion Truck plugs. The Bosch Platinum don't usually show much improvement for the cost if any. But then again someone will say they work great in thier Jeep. I think the Bosch and other platinum plugs work as advertised with ignition systems that are weak, usually foriegn cars. In the older US cars I've had they made no difference. As far as spark plug wires some say Magnacore are the best, but expensive. I used Blue Max, a custom set I had to do the terminals and lengths for my 4.0. Just try and get something with spiral wound core and not a carbon core.
On the air filter, it might help out a bit. Usually with a K&N type setup you need to have it blocked of from the rest of the engine compartment to gain any advantage. On some cars your worst off with one with out the cold box. I think Jeeps are about even. Try this website for ideas: