To my eyes I'd say down pipe only plus stage 2 box which would be just over a grand.
Yes you won't have shiny new tailpipes but I'm certain you could buy trims if that was a big concern.
So, that would bring a GTI PP thus equipped quite close to the price of an R - so it depends on the buyers requirements really.
The stage 2 GTI should be a pretty raw and very quick point to point car 'old skool' GTI style, and the R is an R (accomplished, polished and a step above all else in the range). Depends what the buyer wants really so it's nice to have the choice.
Once the stage 2 software and hardware gets added to the Leon Cupra you've got a real party animal assuming a lot of the sniffy members on here can get over the badge.
And eventually the stage 2 stuff will be available for the R too which would be a real weapon!!!
The stuff we used to dream about when driving mk2 Golfs all those years ago...