i have a giac chip installed. i was quoted the horsepower gains were going to be around 7 to 10hp and the torque would be alittle higher. i have not dynoed my car so i cant give exact gains but i like the giac chip. once it was installed the gains were noticed right away.
I had a neuspeed chip in my 95 jetta and that made it twice as fast as it was. I liked it a lot but I lost cruise control when I installed the chip. That was a few years back, they may have worked that bug out by now.