The difficulty is relative. If you have some experience repairing automotive engines, it not particularly difficult but it is fairly labor intensive. If you don't have any experience, bite the bullet and get someone who has to either help you or do the job for you. There are a lot of parts that will need to be disconnected and/or removed in order to get to the gaskets. You will also need a torque wrench when replacing the manifold. I recommend you take a lot of pictures before and during disassembly so you will know where everything goes when you start putting it back together. Number the plug wires so you know where each goes, and put nuts and bolts for each part in separate, labeled baggies.Also, if you plan on keeping the car, replace the lower gasket while you're in the process. You're almost there anyway and chances are good it needs to be replaced or soon will.