I've looked through a lot of past posts on the subject of Digi ECU chipping, and it looks like people are still undecided on whether ECU chips are worth it or not.
When I bought the car, the guy handed me a chip, saying that he had got it with the car. He assumed it was the original ECU chip, and said that the car must have been chipped by the previous owner, though he also added that it felt no different to a 'normal' GTI.
When I drive it, it seems pretty smooth and responsive, it pulls well in all gears and is pretty quick, but I don't seem to get the same pushed-back-into-your-seat acceleration force I remember from my dad's old Golf Mk2 GTI 8v, and I've noticed that it doesn't seem to really be accelerating much faster than most other cars (and vans/4x4s/MPVs) on the road.
I've read rubjohnny's tuning guide with interest, and am now torn between leaving it with the mod chip in, or putting the original chip in and tuning as per the guide.
I guess for those with badly tuned Digis, a mod chip would make a lot of difference - most of the recommendations for mod chips came from those down on power, or experiencing digi-lag.
It would be interesting to hear from those who have tried both a mod chip, and have tried rub johnny's tuning set up on the standard chip, to compare the results, and to understand which might be better..