what i decided to do was just splice into the wire on the O2 sensor instead of modifying the shielded wire that is part of my car.
i got it hooked up today and it works great. i already adjusted my EHA based on the info i got from the gauge. when i went for another test run my adjustment was evident on the gauge. that's rewarding.
i'm using the Auto meter A/F gauge in 2 1/16". it has 20 LEDs in 3 colors red=lean orange=stoich and green=rich. i payed $60 for it including shipping.
86' 190e 2.3L 16v