OE converter is priced high because of the amount of precious metals inside.. ie platinum etc. The more platinum, the more efficient the catalyst in expense of price.

Honestly the OP probably has spent the price of a OE cat at this point.

i'm not sure how they test it, i'll ask them about it next time and see what method they used. And no godwin, I didnt spend anything close to 1000 at all.
The magnaflow cat was approx 170, the o2 sensors for 190 for both... new gaskets and such were about 30 installation was free so yeah i spent about almost 400

^OEM O2 Sensors?

Althuogh I doubt that is the culprit (it maybe though!).

nah they are denso sensors

hey, just wondering if your car is burning oil? oil will cause the cat to fail, therefore throw the P0420 cat code.

yes it is... then again h22 engines are notorious for oil burning =/