I had real trouble finding a suitable alternative oxygen/lambda probe for my 1992 Rev 2 MR2 Turbo. I can’t find the original Denso part number at the moment, but I managed to find that a Denso DOX-0107 fits the flange size correctly and is 1-wire, it just requires soldering to the original connector. It’s got a Flange 44 type flange which apparently matches the 3SGTE.
I got it from http://service-parts.co.uk/denso-oxygen-sensor-dox-0107
Update 2020 – This sensor is still working strong! So can confirm it is a suitable alternative to the standard Rev 2 MK2 MR2 Turbo Oxygen Sensor