Just my 2 cents worth - My MKV Gti was run in missy daisy style and that car had endless problems with it including new turbo, new manual gear box, new DP, 5 x DV's, and new CAM...needless to say i sold the GTI for the S3...i thrashed the S3 from the first mile and after 2 years i hadnt had a single problem!
Now i dont believe that either driving style had an influence on the cars, and personally i just htink it came down to gettin a "bad" car or getting a "good" car. I dont see the point in runnin a car in but i dont see the point in thrashing it either for the first hundred miles...just dive normally for the first hundred miles