My wife owned several VW Polos but she wanted to purchase another car and decided to use a PCP. An Audi A1 worked out cheaper than the Polo and the reason, according to my dealer, was the great residual value of the A1.
Perhaps it's the same between the Golf R and a similar speced A3/S3.
As John Cleese once quoted ' that's stating the bleeding obvious ' unfortunately many take a long time to truly understand the costs of running a car. Depreciation is a big killer!