I have my 1998 A4 TDI 110hp Re-mapped at the Chipped Uk day on sunday and i have to say i was very impressed, car went on the rollers initialy at 92hp and around 130ft/lbs ish and after the new chip and some error codes removed from the ECU i got 145.8hp and 200ft/lbs and the car is soo much nicer to drive, not done many miles since getting it done so we shall see....
I tried a tuning box from e-bay previous and i was not overly impressed to be honest, there was a noticable power increase but nothing major, and fuel consumption did not seem any better, if not a little worse!
I would try and get a proper re-map, although on a car of that age (mine was the same) they have to remove the ECU and solder in a new chip, deffinatly worth the money though.
There were 3 110hp's there on sunday, mine, a 1998 golf that went on at 105hp (don't remember torque) and came off at 148hp and 209ft/lbs and a 2000 toldeo that went on at 101hp (don't remembver torque) and came off at 144hp and 196ft/lbs i think, so we all got similar values....
Hope that helped.
Adam