http://www.cats-direct-shop.co.uk/lambda-sensors.php

Can anybody tell me which would be the right one for a 1994 WRX please?

Thanks guys.

 

you can use either the 86300 3wire or the 86400 4wire sensor the differance being is that the 3wire earths its self through the exhaust and the 4wire needs earthing some where in the engine bay using the extra wire.
you connect the black wire on the sensor to the white wire on the car and it dosent matter which way round you connect the other two, its the same for the 4wire with exeption of the grey wire which is the earth