If you are going to sand down the Engine Bay to repaint it a different color, you really have a lot of work ahead of you. If you don`t get it sanded to give the paint something to bite into, it will peel.
have you ever used a Soda Blaster? It will take off the paint down to the metal, then the clean up is easier, just wash it down with water and dry. use Phosphoric Acid to etch the metal and remove any flash rust from the water, and POR it or your favorite Primer etc... Nothing looks worse than a lighter color showing through with a darker color painted over it if it gets scratched. All depends n how deep you want t get into this project.
A good Video from Eastwood.
Soda Blaster on My Classic Car from Eastwood - YouTube
A.H. Soda Blasting, LLC - Soda Blasting Demo 1- Paint Removal - Sheet Metal - YouTube
This would be a good time to replace the Sway Bar Bushing on the Fire Wall
Following link is for the TD Bushings 123-323-12-85
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW
Pricey at $33. they are $25 wholesale price form the dealer.
www.benzpartswholesale.com our local dealer.
Also this part# works W0133-1807027 for around $3 ea but Febi brand what I see mostly.
Charlie