Are you asking about the "waxy" material, if so, that is there to protect from corrosion and act as a waterproofing.<ul><li><a href="http://www.autoint.com">http://www.autoint.com</a</li></ul>

yeah will the degreaser remove the corossion protection?

Yes it will, the protection is a wax based material and depending upon the strength of the product, heat of water and engine, dwell time, may or may not remove all.<ul><li><a href="http://www.autoint.com">http://www.autoint.com</a</li></ul>

I use Simply Green, Gunk and Tide. I've never seen or heard of a rusty or water-leaky Audi engine.

What are you talking about? What are the real consequences of getting the protective coat off?