Nothing to do with performance really, the ribs on the top of the valve cover can be ground away to improve aesthetics. Quite a simple mod to do with an angle grinder. Good time to change that leaking valve cover gasket as well. Using a sanding wheel with the highest grit (usually 90) available is the best option, because it is fast and provides a good finish that's not too harsh, avoiding damage to the aluminum. Afterwords the valve cover can be polished up with sandpaper for a final smooth finish, or polished with a buffing wheel for a mirror finish.

Installed result.

Also see

• Alex's 98 Escort build, 97 Escort build, and 97 Tracer build (latest) for more examples and application.
• Ford Escort & ZX2 section for the entire index of all Ford Escort and ZX2 related articles.