Hi,
Is there much diffrence with the Leon Cupra Mk I and the Cupra R rear bumper guys?
Yes, the Cupra bumper looks s*** compared the the 'R' bumper
. The post facelift Cupra bumper, IMO, is a solid painted bubbly thing that gives the rear a rather bland look. The Cupra R bumper is a little chunkier with a cut-out section at the base, in an anthracite colour plastic, gives the rear more definition.
Each to their own though, it's down to personal taste.
You're better off doing a Google image search.