Hi, I am new to the forum. I never use synthetic, I always use AGIP Dino oil. And I go circuit racing about 6-10 times per year. I don't know if the way I treated my cars were right, but it was fine. I had bought a new integra R in year 2000. I oil change at 700km (3000rpm), 1500km (6000rpm), 3000km (8500rpm), then drain interval was 4000km thereafter. Then I oil change right after every track event. Engine doesn't burn any oil. engine oil pouring out of the engine is always clean (golden colour). Then I bought a new RSX-S at 2002. I did the same thing, the engine is running strong. Now, I just bought a 330Ci, the owner's manual said I have to use synthetic, so I don't know if I should stick with my old habit. Any inputs?