To answer your question about them being the same as the OE converter, the answer is NO. They are not the same. A 2001 pickup cat is way different than a converter from a pre 1996 = pre OBD2 vehicle. It is not good to replace only one cat, since that will get the exhaust flow out of balance, which will get the engine fuel control all out of whack. Walker does make a cat that will work on this vehicle, although it will not last near as long as an original equipment cat will. The reason that the aftermarket cats are cheaper than the OE cat is, is because the aftermarket cat does not have as large of a substrate brick, & there are not as much precious metals in the aftermarket cat as there is in the OE cat.

Now, on a vehicle this new, my question is, why is the cat bad? Most times the reason that a cat lives a short life is because of a dirty engine that is feeding it. The reason that most cats die is from either being overheaterd, sulphur poisoning, or phosphorous poising. The sulphur comes from the gasoline that is burned in the engine, and many times using cheap cut rate gasoline will find the sulphur. The phosphorus comes from motor oil. Using the wrong kind of oil, or changing the oil too frequently are the two most common reasons for phosphorous poisoning. Many times the oil that is used at quick lubes is not the correct oil for many of the cars that they service. Oil technology is way more complicated than most people realise.

Before you replace a cat, make sure that all of the oxygen sensors are working properly, and make sure that the engine is in proper fuel control. If this is not done, any cat that is put on the vehicle will not last very long.