Celica ST205 1994 engine oil

Hello, I am a bit confused about engine oils for celica st205. On one of celica gtfour websites it says to put 0w-50 fully synthetic oil, on Facebook st205 group people have different opinions what to put, 10w30 semi synthetic, 10w40 Fully synthetic. Mechanic that I use to service my car said it doesn’t need fully synthetic oil for my car and that semi synthetic would do just fine and that back in the 90s they didn’t even had fully synthetic???

my question is what back I’m the 90s did they use as engine oil for st205? 
can I just use 10w30 semi synthetic and not waste money on fully synthetic?

my st205 is stock, imported from Japan, 180k km on the car.

thanks in advance 

In the 90's it was SG or SH multigrade oil.

SG and SH oil is now obsolete, but using a modern 'SN' semi synthetic rated oil will be far better for the engine.

http://gt4.mwp.id.au/

9 hours ago, Xanadu_999 said:

In the 90's it was SG or SH multigrade oil.

SG and SH oil is now obsolete, but using a modern 'SN' semi synthetic rated oil will be far better for the engine.

http://gt4.mwp.id.au/

Thank you for replying, so I should just stick with semi synthetic and don’t really get fully synthetic if I am not using it for track?

I wouldn't worry about the semi/fully decision, and concentrate on viscosity.

IMO, the important figure is 40, with the ?W figure depending on whether it's a summer toy, or if you use the car all year round.

20 hours ago, Arnasst205 said:

...so I should just stick with semi synthetic...

I have the 3S-GE engine in my car and I have been using semi synthetic for many years. I change it once a year or every 4000 miles and it runs just fine, so yes, stick with semi syn' if it's cheaper for you.