Wipeout has a weapon called quake – I’m sure no one on this forum needs to be told these things! but a weapon similar might suit GRIP. Only instead of deforming the track as it pushes forward it could be a wave of accelerated/pressurised air.
In terms of effect the weapon will push racers into a 90 degree hard turn causing them to skid out and leaving tire marks on the track. So instead of my initial though, clearing the leaders out by throwing them up and forward (frustratingly), the force of the weapon should push them down and into that hard exaggerated turn.
This would not be entirely frustrating to all leading cars but would also have the potential to cause some havoc i.e. push vehicles into scenery and other vehicles.
Similar to the EMP but instead of affecting all racers it only hits those ahead of you.