Just use the recommend grade and change it with the filter twice a year or Every5/6 K miles. And just use "ordinary" oil. If engine is older than about 80K do it more often.. I just use Comma oils as I buy in bulk. I have an Austin Mini with about 200K on and my old cinqucento did 174K and engine was still great when she rusted out. For what it costs I just change oil more frequently. I also check oil level every couple of days..my current punto 1.2 8v has done about 3500 since oil change and hasn't used a drop. She's only got about 70K on though. ...change your oil often...it's the engine's blood