I reported this to VW when I first got my gti.
I have found that the idle when cold or when I'm sat in a lot of traffic the idle seems a little lumpy.
Also when It's cold the engine seems to stutter for a fraction of a second in first around 1500-2000rpm.
When I took it to my local dealer they said someone drove it around d the car park and they said it's fine.....great thanks for the great diagnostic!
Anyone else find this with there or is it just another in my long list of warranty problems