I'd say its the comparison between the power and feel of the Fiesta VS the Falcon. Changing engine oil alone will not do much anyways. More a personal feel than anything else. Even if you do feel a slight difference, it will go away very quickly and before you know it, it'll be the same Fiesty you've always known. Maybe bolt on a supercharger kit then?
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Wifey's always complaining about how gutless the Fiesta is and yes I do agree to some extent (despite the improvement with
ecu tuning) but then again she's comaping it with the modded Polo Gti which has double the power.