Okay was in my local garage a few days ago and came accross an additive for cleaning the fuel sprayers in the engine and also to help lower Co2 emmisions.
I wont be doing many tests for this one all I will do is give you some details on it. As really we shouldnt notice much as its internal. It may have a noticeable affect on the performance but again I am not sure.
Anyway its in the tank at the moment so we will see how things go. I will post in a day or so with full details on the product.