I've been thinking (for once!).
VW put a KO3 in the standard GTI to give 197hp. For the Ed30 & Pirelli they upgraded to a KO4 to produce 230hp.
Now VW obviously did plenty of r&d and testing so you have to ask why did they put a larger, more expensive turbo into the special editions? As well as upgrade other internals to handle the extra power, all adding to the cost (yet they didn't upgrade the brakes!)? I'm asking this because many of us have mapped the KO3 to 240hp or so with a stage 1. Surely VW must have looked at this as they could then have produced the Ed30/Pirelli for much less, but still charged a premium. VW must have tested and realised that going to 230hp on the standard GTI was too much and compromised the car somehow.
I would hazard a guess that the average punter who bought a new Ed30 or Pirelli didn't have a clue that there was a different turbo, etc. They bought it for looks, exclusivity and the extra bit of poke over the standard GTI; extra poke that can easily be obtained by a changed map as we (and VW) know. Yet VW's engineers didn't do this and I would surmise that VW's engineers know a little bit more about their engines than most aftermarket tuners. I wonder if Bosch wouldn't agree to a different map? (I'm sure that's rubbish-correct me if I'm wrong).
I suppose I'm trying to understand what the compromises were that made VW upgrade the turbo for a relatively modest power increase and whether all our remapped KO3's are going to have problems in future.