Hey I phoned Honda and asked them about oil as in my previous type r's 10-40 semi was advised, but I just bought my third type r (ep3) and a Honda booklet came in with the wallet about recommended oil and that said to use Castrol longtec 0-30 fully. So I phoned Honda to inquire and the guy said the oil Honda use if they was servicing your car would be Castrol professional series 10-40 semi this is because it's more cost-effective for Honda and the owner as type r's use some oil, but he said 0-30 or 0-40 fully is fine and could help keep your engine in good nick but it's a thinner oil so could use a bit more, he said if I could afford to keep putting in fully synthetic go for it. (Honda used to use Mobil 1 but have switched to Castrol as they feel it's a better oil). So I've just had a service with forte advanced engine flush, stuck in Castrol Edge 0-40 fully and a new oil filter and my car feels more responsive, quieter and smoother, I'm happy using this oil and I don't seem to use much on mine but I suppose it depends on how you drive. Whether it's the same on an fn2 though I'm not sure. I would go for good quality oil though hope this helps. Forgot to mention I could not find Castrol longtec oil apparently this has changed to Castrol edge.