I was told it was purchased at the same time as the car, from the catalog. This clearly isn't an addco (that is the brand in the catalog)

Looks a little like a bar I saw once that I think was sold by SASAB? Not sure, thats just from memory. It does look pretty substantial, but I wonder if it's actually any better than an OE 900 rear sway bar?

The previous owner said even on the softest setting the car was very prone to oversteer.