I have been following 15 k interval and MJD doesn't feel Noisy or rough. except until my second service. So changed the engine oil at 13000 kms although SA was reluctant to do that. there is lot of dust in Bangalore,where in i can't drive two wheeler without spectacles. So when your car runs for say 25000 kms, although it's 10000 kms from oil change still it will feel smooth and refined. 7.5 K will be good but most of the Synthetic engines oils can go upto 20000 kms, but FIAT conservatively put it as 15000 kms. Also it's how you use the car mandates the engine oil change, if it is subjected to lot of start stop or B2B traffic I would recommend changing at my be 10000 kms. because Diesel engines are run max 3500 RPM but petrol engines can go to 6-8000 RPM with higher temperatures than diesel.so petrol cars would need more frequent change IMHO. You should be able to listen to the pulse of the car, when it asks for engine oil change.I am sure we all as we love FIAT. Fuel filer can be changed at 15 K,just go for Oil filer and Oil.I used to get 20K kms with Mobil 1 in my earlier car, i am eager to try it this time.