Merc DFI always.
Merc DFI always.
Pennzoil Synth...XLF if Synth not available.
Walmart super tec for my 2.5 and it runs just fine and has been used in it for the last 12 years or so.
Quicksilver premium plus
Pennzoil Premium for years on both yammies and pro xs's. Over 40 gallons every year and never had a problem. Also seafoam every other tank.