Buy the 1.6 I think. Anything you still want from the 1.4, bar the engine of course, just take off and put on the 1.6 if you can. I say this as I don't think its as simple as taking the 1.4 out and putting the 1.6 in, I'm not sure the ecu's are the same. Plus there are also 2 types of 1.6 engine.