I just found this thread and wanted to post a question as you guys seems to know what you're talking about!
I bought a tunning box from Chip Express for my 2009 159 ti 1.9 diesel. Initially it was great, simple to install, more power, torque, mpg, etc. However, after about 12 months my clutch started slipping (with that nice smell!). Didn't happend all the time, maybe 1 out of 5 outings, and did not seem related to how fast I was accelerating or whether the engine was hot or from cold start. If you removed the box, no clutch slip.
ChipExpress customer services just said reduce the power setting on the box (it had always been set at their recommended middle setting). Each 'notch' down seem to make the clutch slip less but even the lowest setting I would feel a slight slip (maybe 1 in 10 outings).
I removed the box and took it to an Alfa dealer to ask to take a look at the clutch, they said all was OK after they test drove it (only have their word for it and they wouldn't do a closer examination without charging me... unless they found something wrong under the warranty!)
Mileage 12,000 when fitted; 24,000 when started slipping.
I've given up with ChipExpress customer services as they don't think it's anything wrong with their box! The box has been disconnected from my car for 6 months now, never slip since then.
Thanks for any ideas [ebay it?