First off, you need to label all of the electrical and vacuum lines connecting to the intake manifold. This will make reassembly much easier. Then, there is a torque sequence to be used during disassembly and reassembly.
This image is of the TIGHTENING SEQUENCE. Reverse this to take the manifold off. This is important so that the upper intake manifold is not warped at all, which would decrease the quality of the seal. Be careful during disassembly and reassembly to avoid bending any lines or tubes. If things are in your way, disconnect them rather than pushing them to the side. This will avoid pinching inner linings which cannot be seen visually.
As for the gaskets, (as far as I am aware), Chrysler's (Dodge's) official stance on the manifold gaskets is that they are reusable. However, this is if they ALL look good under close inspection. Any tears, "melting", or other damage means the gaskets should all be replaced. They are not expensive, and I believe they all come as a set including both upper and lower gasket sets. Personally, I would recommend replacing them regardless. This would be a good preventative step to help extend the life of the vehicle. Also be sure to check the cooling line O-rings and replace them as necessary, following the criteria above.
Good luck and I hope this helps, even though I see it is a bit late.
