4A-GE and syntethic oil

[NoHachi]

There is almost no real fullsynthetic oil on the market anymore. But beyond that, oil is just oil, synthetic is just manufactured a bit better sometimes.
What you need to make sure is that you get the recommended oil weight/temp rating (is 5w50 within specs?) and that you get the rest of the specifications good as well...there is a bunch of G-xx numbers on the oil that should match your specs in the instruction manual. Not many people do that, but it can make the difference between an engine that last 200.000 and 400.000 kms