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

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

Not many 75-90 GL4 options out there unfortunately.

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.

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.

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.

Fair enough, I guess if MR2QIK hasn't had any dramas then I'll just stick with my OEM one.  I have also been browsing the forums on mr2.com and they also reckon that OEM diff can handle a fair amount of power. 
 
However I think because the diff and gearbox is so close to the cabin in the MR2, the noise and the feel of a mechanical LSD can be offputting for many people - I had a drive and a ride in a 300 kw S14 with a Kaaz LSD and it felt quite nice, no 'crunching' or major whining with the added traction in a straight line, not so much around corners.
 
In other news, just bought a sidemount intercooler kit and 4" intake - just need a down pipe then I'll up the boost from 13 psi, just to get a bit more extra power.
 
I'll post pictures up when they get here.
 

I'm guessing that a Quaife wouldn't be loud? They use gears instead of clutches to achieve their LSD functionality.

purple5ive

i hate my mechanical LSD its quiet noisy and chatters when cold A LOT.  stick with a viscous one if you can. im going to change my gearbox oil soon but not sure what to go for now lol
cheers

 
My first MR2 had a plate LSD, it was noisy, tried a few oils with varying degrees of success, but still noisy.  One of them finally worked fine, no noise at all.  From memory it was a mobile synthetic oil. 
 
Cheers