Hello all. I have a 2006 Accord w 79000 miles. I have always used PYB since 20000, with 4000 - 4500 oci. I wish now that I'd used synthetic, would I see any benefit to switching to Penn Platinum now, or should I just continue with YB. I plan on driving this thing till the wheels fall off. Also if I stay w conv., should I switch to High Mileage oil? thanks