Ben has even had the box off my own car, my car now runs with his box and without issues. Im not sure what the issue is but as Sherlock Holmes famously said, if you rule out every other possibility whatever is left, however improbable must be the answer 
People seem to assume that just because the car runs ok with the box off that the box must be the cause but the box increases boost pressure and if you have a leak somewhere the increased pressure could increase the leak just enough to bring on the engine light, standard boost pressure may be low enough to not trigger it.
I had this issue with a customer in Portugal, it took the garage 3 months to eventually find a crack in the intercooler, once fixed the car was perfect, you may well find when you remap it you'll have exactly the same problem. This car without the box drove without warning lights but when dyno tested was down around 20bhp and 50nm on what it should have had, this is what convinced the owner and Abarth that there was definately a problem. Its difficult to get any garage to spend alot of time checking for an air leak when the car appears to drive normally when not tuned.
Daron,
As you know, initially I thought it was down to something with the car, however Abarth have replaced, many many many items on the car, including the boost pipes, sensors, turbo, cat, ECU etc.
The car has been on a rolling road when standard and has showed that the car is running as expected.
The car has also been in a friends garage for a week, where we practically took everything off, checked it, replaced it. we found no split pipes, no crackes - intact the only thing we found what that my exhaust was blowing a little - this was then fixed.
He, Abarth and I are 100% confident there is NOTHING wrong the car now.
The box cause problems where the car will not start on occasions (removing the box from the loop resolved this).
Now I'm not saying there is a problem with the box, as Daron has said, Ive had 3 boxes, all which were confirmed ok by Daron. My car simply just doesn't seem to agree with them. I have tried an older style box with 3 connectors, and 2 new style ones (with the setting on 1, it still causes problems).
