Exhaust and Cat questions

[Mohit]

Originally, I planned on installing a Borla Pro XS or a Flowmaster HP2 muffler to my 91 318is and getting rid of my empty cat. I read up some more and apparently the cat plays an important part in reducing the raspy sound the M42 gives off, so I want to change the cat before I do anything with the muffler. The muffler shop quoted me $350 for a new cat + installation, but that sounded on the high side for me, so I wanted to see how much I could buy new cat for. Will any California legal 2.25" in cat work? Can I just weld in something like this or this and call it good? When I see if it is compatible with my car it says it isn't.

Also, my car doesn't have any exhaust hangars, I think the muffler is just somehow bolted in. Do I need the hangars if it is an aftermarket exhaust?

[Josh1254]

Alot of cats sold by exhaust shops are crap. If you plan to keep the car in California buy a quality one otherwise you'll pay to do it again. Magnaflow high flow cats are under 200.... Keep a resonator, cat, and muffler on the car.

[Mohit]

Alot of cats sold by exhaust shops are crap. If you plan to keep the car in California buy a quality one otherwise you'll pay to do it again. Magnaflow high flow cats are under 200.... Keep a resonator, cat, and muffler on the car.

If I get a Magnaflow cat, can I just weld it right in? Do I need some clips or hangers or gaskets or anything?

[Josh1254]

Weld it in. Your exhaust should have a support bracket by the transmission, rear subframe, and on the muffler. You can always add another one if needed.

[cgk_iii]

Those MF cats are only good for a year or 2 though. But yes u can just weld it in and you're good to go

[Mohit]

Would this this Maganaflow 37105 work? It seems to be CARB compliant and the right size, 2.25".