replaced O2 sensor, now running like (insert 4 letter word)

[Nathan Engelbert]

Replaced the O2 sensor yesterday and today on the 89 90q.  In order to get
the old one out, we had to remove the cat, cut the top off the old sensor,
and put a socket onto the sensor.  Big breaker bar, etc.  Putting the cat
back on today was less than fun, and I'm not sure we got it 100% in the
correct orientation.  Also, while removing the cat, the end that goes to the
rest of the exhaust made a pretty decent sized hole in the exhaust part from
bending back and forth to get the cat out (muffler tape?).  I
soldered/crimped/taped up the new sensor, Bosch 13913 (generic 3 wire sensor
recommended on 20v.org), and started the car.  The car sounds awful and
there is some exhaust exiting before the catalytic converter where the
flange from the downpipe meets the cat.  At first the car wouldn't idle,
until we turned the screw on the throttle body that moves the rest point of
the throttle body.

So, what's the correct orientation of the catalytic converter, the O2 sensor
right now is almost contacting the bottom of the car pointing up and toward
the passenger side?  And, what could I have screwed up to make my car run
totally differently?

TIA,

Nathan Engelbert
89 90q