Hard to tell from just that one picture, would have been more helpful to see from top but I think it's just a normal

'banana' style boot spoiler.

They aren't very expensive, that one happens to be fitted further up the boot but also see them mounted sometimes further down where spoilers typically go at the back end of the boot.

If you google

"MR2 MK3 banana spoiler" you should find examples to double check and see if that's the one you are inquiring about.

Edit: Wow just noticed this question is quite old, I figured newest thread in this section would be actually new so never bothered to check date on it.

My bad.
