I'm looking for a replacement Bosch O2 sensor, and found two Bosch Part numbers for the same item: Ferrari part number is: 121515 In checking RockAuto, and the Bosch Parts Finder sites, they both list two O2 sensors: Bosch Part Number 15735 and Part Number 13957. Bosch Part 15735 is listed as a "Universal Type", while the Bosch part 13957 is listed as a "OE type", both are 'before catalyst, Interval = 60000" Theres a $57 price difference between the two Bosch part numbers, so which one do I choose for my 84 QV???
The universal type does not have the connectors at the other end (has just stripped wire instead). So you need to cut the connectors off your old O2 sensor and splice the wires together. It comes with posi-lock connectors for splicing the wires. I did this for my Mondial T, though the exact model number was different than the one for your car, worked great.
Ferrarilou is correct, I have seen a couple threads over the years on this subject..the oem is "plug and play", the "universal" requires a very simple splice of the plug end.
