@Shankar, one question. Why did your friend change the oil to Bosch synthetic oil? Did he maintain the same viscocity grade recommended bu Fiat? Also, its better to change oil filter along with oil change. Has he done that? Am afraid, during warranty period, its better to stick to manufacturer's recommendations and get any engine related work done at authorised service stations. Btw, Fiat uses Selenia synthetic oil, which is fairly good enough oil itself.