You will have to try
a few, see how your engine feels and sounds on each and reach a determination as to which one quiets it down the most.
Hopefully nothing happened to the engine that makes it clack and clatter like it should not, that said, I would first try some kind of 30 or 40-weight Pennzoil. Whichever one ends up working best for you is for you to find.
just did a bunch of top end work on his 00 legacy
If the timing or valve adjustment is off, and if that is why it sounds not right (does the car stall? Accelerate well? Accelerate bad? How bad is it?) is off then
and it's not the oil fault.