I want to fully polish my intake manifold but I know once I take it off I have to replace seals. What seals and how many? If those are the right questions

 

Your plenum or manifold? Plenum you don't need anything. The manifold you should just need the one (or two?) gasket(s) between the manifold/heads. I suppose you could change the injector seals while its all out, but other than that you shouldn't need anything.

As long as you've got it off and polishing it, you may wanna gasket match the intake ports...if you're not scared...haha

 

Wait what's the difference between plenum and manifold..

 

The plenum is the big squarish thing that you see when you take off the engine cover. It's got the throttle body connected to it..6 bolts on top..

The manifold is under that and has the fuel rails connected to it.

 

You don't need to replace your gaskets, but a motordyne aramid gasket would be a nice upgrade over the stock one if you plan to remove your lower plenum:
http://www.motordyneengineering.com/...products_id=50

When you put your plenum back on, be sure to follow the torque specs and tightening order in the service manual. Also make sure the little rubber ring around the oil filler doesn't get stuck between the upper and lower plenums...it happens to a lot of folks.