It may not be critical per se.
However it's a very nice splash shield to protect to fog lights and wiring/connectors inthe front
Plus it really does act as a air deflector to keep underside air out of the engine compartment. When this high speed air does get in there it lifts some weight off the front wheels. That is very bad as one can imagine!!!
BTW - All SVT's have it, but then again it's different then the stock piece...
