1993 Volvo 240 - Floating flange header with donut seal - may need to replace CAT and the pipe extension behind it.
Do I need to get a Volvo unit or will aftermarket work (Magnaflow). Has 02 sensor at front of converter.
IPD sells one but is with fixed flange so they say I would need to replace the header pipe with a fixed flange ending. But I see there are some on eBay etc., with a floating flange available saying it is suitable for a 93 240 at reasonable prices.
Will I need to replace the wire 02 or is it universal fit. Don't want the check engine light to come on after I'm done.
Thanks from those that have done this and can offer any recommendations - do's and don'ts.

For what it is worth, my mechanic replaced my cat with a Magnaflo on my 940, and I can now easily pass CA smog.

on my 1990 there is an O2 sensor up front ,inthe downpipe but nothing after the cat..

Newer cars have a 02 sensor that checks if the cat is working. i htink its designed ot make you spend money and worry about stupid idiot lights so you run to a dealer.

If it doesn't have any other sensor after the cat. I'd replace the cat with some exhaust pipe. bypass it.

if you need to pass a smog test, that might be needed in california, here in BC Canada it was omitted and we did have a lot of cat thefts.

the cat wont affect how the car operates, unless it plugs, or unless there i a sensor that measures OT to confirm it works. I've taken and knocked the porcelain honeycomb guts out of them before as it started to rattle.. a plugged mufflersystem is a funny thing to troubleshoot because its not the first thing you really even think about.

I've never owned a car new enough to have ABS or more than one cat or airbags so I'm of limited help in what changed by 93
i did put a new one in my 1990 240 once, because it needed to pass the smog test.