How important is the egr?

EGR is an emmisions item but does not effect performance. It closes off at periods of low vaccume. It is designed to put exaust gasses back into the intake to reburn it and lower combustion chamber temps which reduces NOX gasses. If emmsion's isn't an issue I don't see why not. There are kits availiable to delete this and keep code from appearing.
 
There is no upside to deleting the egr except reducing engine bay clutter. It admits small amounts of exhaust gas (inert) to the intake flow at part throttle which cools the combustion chamber allowing the ecu to run more timing, and less fuel. This reduces emissions - especially NOx - and increases fuel mileage. It's shut off at w.o.t., so removing it does nothing to enhance peak power. Removing it without turning off the egr function in the ecu (chip, tweecer, etc.) sometimes results in detonation problems as the computer still pulls timing and fuel, but without the exhaust gas present, the result is too lean a mixture. Of course error codes and check engine lights also occur when it's removed without turning off the function in the computer.

If I were you, I'd buy the correct spacer and leave it functional - it's a rare case of win-win.