to either allow clearance for larger brake setups i.e. running deep dish rims and wanting to fit them over brembos for example
however most do this as it widens the wheel track, giving better stability and handling
this was a flaw in the
mk3 ibiza cupra as the rear was narrower than the front, making the back end twitchy. Adding spacers gave instant stability to the car. The Leon does not suffer from this, but spacers is a very cheap and simple aspect to improve the handling of a car
many run spacers on their leons on here and report improved handling