cheers

 

Guards the diff

 

Its a metal plate that guards against you smacking your diff casing off the road when bottoming out. It should disipate (sp) the forces over a wider area thereby, hopefully, saving the casing from taking the full brunt of the shock at the point of impact.

Can look neat from the rear but not usually required on a road car unless you like to launch off things like bridges, railway crossings etc.