Theres a lot of info on here re this issue.
I have the gizmo fitted from Ebay, I would say the only problem is it takes about 20 mins from startup for the engine map to return to normal.
There is a view that a timed relay instead of the standard relay works better.
I have not been able to find one suitable yet, but when I do I will make the change.
The down side of the map change is you use more fuel in the early stage of running, so if you are on short runs only then it is an issue, if how ever you do a lot of longer runs, then there doesnt seem to be a penalty.
The other issue I have is I cant remove the gizmo, cos when I do then the check engine light comes on, and I have no Turbo boost. If once started I remove the pwer lead to the relay, thus dropping it out then the map changes and I have normal running.
I dont understand why this happens, maybe I have a temp sensor not functioning fully.
Dave