On the right bank what has to be removed to change the spark plugs. thanks

 

Are you asking right bank as standing in front of the car or right bank while sitting in the car?

One side is the air box and assicaited intake piping. Other side is basically nothing other than the plug cover.

 

Are there gaskets or seals that need to be replaced when changing plugs? (like perhaps on the air box?)

 

Nope. It's a very striaghtforward process. Taking the airbox off (all the way up the intake manifold) is really the hardest part. The rest is a breeze! Search the 300/400 forum. I believe there is a write-up with pics somewhere.