none as they are pattern copys
A OEM converter should bolt in exactly like the original, an after market may have to be cut and welded in.
Sensor 1 would be before the catalytic converter ( upstream ) Sensor 2 is after the catalytic converter ( downstream )
From what I understand , the oxygen sensor ( s ) upstream of the catalytic converter is used in the control of the air / fuel ratio . The oxygen sensor downstream of the catalytic converter is called a catalyst monitor and monitors the efficiency of the catalytic converter
The catalytic converter is found in the exhaust system between the engine and the muffler.
There are no differences. High flow catalytic converters are not really high flow; the catalytic converters you have on your vehicle are as high flow as you need them to be. A "high" flow converter will either be of a larger diameter, or the inside is made in such a way that there is less restriction to exhaust flow.
The catalytic converter(s) would be found in the exhaust system between the engine and the muffler.
Direct to fit Catalytic Converters come ready to install with all parts pre-welded. These are better for the DIY professional. Universal converters are cheaper, but require cutting, welding, etc. These installations are best left for the shop professionals.
Crawl under the vehicle and look between the engine and the tail pipe. You will see the catalytic converter.
In the exhaust between the engine and the catalytic converter.
Catalytic converters are located in the exhaust system between the engine and the muffler.
A catalytic converter on a 2001 Chevy Venture van is located under the vehicle. Follow the exhaust pipe from the engine to the rear of the vehicle. The large object connected to the exhaust pipes between the engine, and the muffler at the rear, is your catalytic converter.
It is in the exhaust pipe between the header and the catalytic converter. That is, it is downstream from the header, and upstream from the catalytic converter. The first O2 sensor is located under the hood on the driver's side. It is located in the exhaust pipe between the header and the catalytic converter. The second O2 sensor is located in the exhaust pipe between the catalytic converter and the muffler. The wire runs up through the floor board where the connector is located under the carpet under the driver's seat.