I can't tell you too much but I know a little... First of all some OBDII scanners can report live O2 data (my ScanGauge can), so you could watch it and see if it looks OK. That might give you some idea about the wiring. The ScanGauge is really cool but costs about 200.00, but it is cool... I did replace my cat and I remember the exhaust system is in two pieces. If you need to you could try lowering it just by disconnecting the hangers, but you would want to loosten the manifold bolts first. Sounds like Chas knows more than me. Good luck.

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra