I owned my GTI VR6 for three years. I was disappointed by the gearbox (the ratios are too close - rev limits too easily), but generally happy with engine/transmission. Stock tires were harsh and gave poor handling. Electronic gadgets mostly disappointing: one touch up/down windows frequently malfunctioned, auto-dimming mirror had ghost image of headlights, climate control hard to shut off, and the rain sensing wipers used the wrong interval in certain conditions. The audio system was much better than in my previous Passat though. The interior materials were of average quality (thin leather, cheasy plastic levers and knobs on seat break easily). The car was nimble with its short wheelbase, but the suspension was harsh and sloppy in manuevers. It rattled like mad.
Climate control, except turning it off.
Get rid of the blue dash. Use better leather and vinyl. Wider ratios in transmission. Less aggressive ABS. More padding in dash and console to rattles.