Car is a bone stock 1999 civic si 1.6L B16A2, mileage is just over 160,000. Car is driven fairly easy and garage kept in WA State and really never see's temps below freezing. For the last ten plus years been running chevron supreme 10w-30 (OCI 3k), engine is still strong and no smoke but I do see a drip or two of oil a day on an oil pan on garage floor. Should I go with a 5w-30 or stick with 10w-30? Should I go regular oil, blend, full synthetic, high mileage? I want the engine to run as smooth as possible, protect the engine as best possible and also try to stop the small oil leak if possible (not sure of source) but think a head gasket. Any recommendations would be greatly appreciated.