I suppose we'll have to ask him to confirm, but I thought he said it was a Penrite 75-90.

MR2QIK and Reddtarga, sorry bout the confusion guys - typo error. 
 
I'm using Penrite GL4 75w - 80, and there is a massive difference to the other oil I was using (Repco GL5 Gear oil).  The previous oil felt notchy, hard to shift in the mornings...especially when changing to second and third.  One of my mates who has a Celica with a 3sgte reccomended the Penrite oil.
 
What oils do you guys prefer?

I use Caltex 75-90 GL4 Easy Shift. Works well.

Not many 75-90 GL4 options out there unfortunately.

MIDNIT3, check out this article:
http://www.widman.biz/uploads/Transaxle_oil.pdf
GL4 oil may be hard to find but it could could be worth the search.
 
The Penrite GL4 oil (same as you are using) is pretty cheap but still worked fine in my S54 box with smooth shifting even when pushed hard.
However I have now filled up with Amsoil GL4 75W-90 manual trans oil, (MTG) it's a full synthetic.
I only changed because of the heavier grade and I do a few track days. Although it cost a lot more I can't really notice much difference shifting at this stage compared to the Penrite.

I use Nulon SAE 80 Smooth Shift Manual Gearbox and Transaxle Oil (GL-4)
http://www.nulon.com.au/products/Gear_and_Differential_Oils/SAE_80_Smooth_Shift_Manual_Gearbox_and_Transaxle_Oil/#.T87CHdUnz-0
Nulon SAE 80 Smooth Shift is recommended as an alternative where DEXRON® III is required in manual gearbox for better shifting.
It replaced the 'smurfs blood' that was in there before and haven't had a problem, always shifts well from cold even hence ideal for the early model boxes with ****e synchros.

I used that in my AW11. It's ok, but it's a bit too heavy when cold & not enough when warm. That was on a pretty worn box on its last legs though.

Thanks for the link Reddtarga, ill definitely check it out. Im thinking ill try either the Amsoil or the Caltex GL4 for next gearbox oil change.

Now another quick question....I have viscous type sealed LSD so ive been led to believe I don't need a LSD additive, however if i change the LSD to a Quaife one or something similar, would I still use the same GL4 oil?
I have plans to slowly build a 300kw car ...or close to :) Depends if this engine breaks lol.

MIDN1T3

Now another quick question....I have viscous type sealed LSD so ive been led to believe I don't need a LSD additive, however if i change the LSD to a Quaife one or something similar, would I still use the same GL4 oil?
I have plans to slowly build a 300kw car ...or close to :) Depends if this engine breaks lol.

Some discussion on it here:
http://www.mr2australia.com/topic.asp?TOPIC_ID=21108&whichpage=6

No, you shouldn't need any addictive for the OEM Viscous LSD.
 
Long story short, the lack of a definitive solution to tranny/mechanical LSD lubrication is one of the reasons I never bothered with a mechanical LSD. From what I've heard/read, you end up with a trade-off in either direction.
 
I have no complaints with my stock LSD & over 300rwkw. But then again, I've rarely even driven an MR2 with a mechanical LSD. Luan/LMT has one & doesn't praise it.

I've driven an MR2 turbo with a mechanical LSD and you sure damn know its there from all the noise lol
Having said that the only LSD I'd put in mine would be a Quaife ATB.