I have a gdi plus4 and have had the ECU remapped by Williams Morgan -- fantastic result -- I had wanted to do it as I was told it would improve the MPG -- well... it did improve the MPG - from average33 to average 40 BUT .. it also gave a big improvement in grunt from about 2500revs --I do NOT have a fancy manifold, just the standard one -- Best value upgrade ever for the Mog!
