oxygen sensor 4-wire p/n question 94 E320
 

A while back I bought a MB 4-wire oxygen sensor labeled p/n 0 258 003314/315 for my 94 E320 wagon. I tried to install the new one the other day. I believe I needed part 0 258 003314 (aka 13314). Both the one in the car and the new one in the bag have 4 wires: one black, two white; one gray. When I pulled up the passenger carpet I noticed the one in my car has two plastic connector plugs while the one in the bag has one. I was considering splicing the new sensor into the old wires, instead of sending the part back for exchange; does it matter which white wire goes to which? Thanks.

Also wondering how to splice the pair of white wires
 

two of the 4 wires are white--when splicing, which goes to which? does it matter? I searched archives, but none I found addressed this issue. I was thinking of locating the splice under the passenger floormat.

" Generic " wire colours are:
Black = O2 signal
White = O2 sensor ground
White = O2 heater ground
Grey = 12 volt power to heater element. ;)