Hi Jossi
I don't recall any of our Club members having chipped the 1.4 petrol.
AMD Technik, the only UK tuner I have seen offering the conversion, claims an increase of 10bhp and 10 ft.lbs torque and it costs around £400.
Some companies will reprogramme the ECU and let you try the upgrade before deciding to buy. I'd recommend you do this if possible.
Cheers Spike