Header install on a 4th gen
#14
I think the front O2 sensors are important to have working, but the back ones (after cats) are not. I think you'll be running rich if you're not getting proper readings from the fronts.
#18
i addded wire to mine, solddered the wires and shinkfit em. do you have 4? my 93 has 2. there are bungs for back 02s on my y pipe. i am thinking about putting a/f gage in and using them.
#20
i didnt need to extend one, the other i extended the wire. thats when i had one wire 02s. i now have heated 02s (you already have) and they came with longer wires which didnt need extending. i had to run different wires for the heated ones anyways. with low voltage wires i try to always solder.