Okay, I allready splitted the inlet into:
elbow, throttlehouse, manifold, plenum, fuelrail, injectors (greased), and fuel regulator

I'm planning to have the elbow sandblasted.
And I'm polishing the fuel rail.

So what I'll do to the inlet manifold and plenum is "bead" blast it.
After that I'll clean up the manifold/plenum before painting and re-assembling.

Thanks for the advice m8.

Sometimes I almost loose motivation in all the things I want to do to the engine parts, it's the first time ever I'm in a "rebuild-situation". But never the less, there's time enough, since I'm saving money for the new pistons and a Alcon 6-paddle

Do you have any pics of your inletmanifold (or parts of it), at the end-result?