I found where it was discussed
   http://www.mr2oc.com/printthread.php?t=305066&pp=50
 
So it would be the MX73.

Mrskylighter
When I say 750-1000kg I was just going off what the OEM Toyota one was rated at.
 
Here are some pics of the OEM Toyota UK one and also an aftermarket Draw-Tite branded one from the US.
  [attachImg]
 
 
Knightrous are you making a new one from scratch or just modifying yours? If from scratch can you have multiples made?

 

Hallo dear mr2 friends!
Can someone tell me if this trailer hitch, here in the picture, with the Toyota nameplate, whether original for MR2 aw11 or not?
Exactly the same was offered to me! 
Best regards

Hallo hallo,
Does anybody know if the Toyota part above is exactly for mr2 w1?

Hi there,
 
Yes the Tobo towbar was officially offered by Toyota in the United Kingdom for the AW11.

Mrskylighter,
Thank you for the faster answer.
I have already bought one in England.
But unfortunately I have no accompanying document and so without I can not mount in my mr2 in Germany :(
Where could I get something like that?

Page 2 of this thread has installed pictures. You may need to drill some new holes through your metal rear bumper reinforcement if they are not there already.
 
Once you take the bumper of the car I think it will become obvious what you need to do.
 
I have never found a manual for the toyota one.