A bad cat vs a clogged cat is the same outcome, a new cat.

If the o2 sensors are working properly a P0420 is usually nothing else but a bad cat.

Only thing wheels locks prevent, is owners taking off their own wheels.

There is nothing more dangerous and expensive than a code reader in the hands of someone who expects that a code is a magic bullet.

I have a bunch of different things that will do it. But BimmerLink is a good one. Also useful for reading codes etc.

No I just bought the battery and installed it myself. I have the tools to register it.

Try the dealer. I bought an OE battery at the dealer last year and it was cheaper than Costco or Canadian Tire.

At -30c you want to wait for the oil to start moving at least. Doesn’t mean you want to sit and idle for 20min but at -30c I’m guessing your windows aren’t even clear at that point.

I live in Quebec so I feel your pain.