Lots of confusion in here! Pretty sure tuners are getting nigh on (if not over) 300 ponies out of the GTI VI. Makes me wonder why the older engine got put in the R? I guess the E888 gets heavy on the carbons when the power gets upped?
It was already developed for big power (S3/Cupra) so there was very little development work to be done. E888 might re-map to high power but it doesnt/can't meet tough VW durability standards or Euro emissions legislation with just tweaked calibration. Beefing up the EA888 wouldve taken time and money, effecting the margins on R sales. Simple solution, tweak an existing, proven technology. Job done.
Nothing to do with engines lying around, they dont build anything they dont need! EA113 is considered to be a pretty strong engine. Over-engineered infact. The EA888 is cheaper and easier to build, how strong it is, remains to be seen.
To add to the confusion, I'm pretty certain there are EA888 variants with K03 turbos as well.