The 3.7l uses a throttle body injection system, it looks like a carb but it contains two injectors mounted over the intake manifold. The spark plugs are located under individual coils. There is no distributor or single coil but the 3.7 has 6 coils. The parts that you think are injectors next to the fuel rail are the coils and wires.
There is one nut that you will have to remove before pulling each coil off. Blow off any dirt or sand away from the upper manifold before pulling out the coils and plugs. The spark plugs are down deep so don't drop anything down there like the retaining nut or it will be a nightmare to get out. Pull straight up, pop, then use a spark plug socket with the rubber insert to loosen and pull the plugs out, 5/8"s I think.
Normal spark plugs won't last 100k, only those high priced platnums. You probably have regular NGKs, about 3 bucks each. They lose their proper gap size over time so changing them is not a bad idea.