I had a 3DR Manual Steel Grey Ed30 for over 2 years.
The car was great, apart from the brakes, utter shyte! sorted with some S3 Front and rears.
I mapped the car with Superchips, and it was the worst thing I did, it came off after 150miles. I never mapped again, standard power delivery IMO was far better than the SC BF offering.
My car had a few warranty claims, creaking seat base, Dual mass Flywheel and a steering rack, I don't think these are just attributable to the Ed30.
I have never driven a KO3 Gti, so can't comment. Ed30's on forums seem to command a far higher price than on Autotrader/PH. As Hurdy alludes to, DSG's are at times temperamental, warranty is a must.