I'm a bit surprised that one would need to be replaced in such a new vehicle. Factory cats contain far more precious metals than aftermarket ones and do their jobs better which is the filter the exhaust gasses but the car itself isn't likely to run any better as a result of having a factory cat over aftermarket, unless perhaps it's a vehicle where the exhaust system back pressure plays a part in the power output of the motor. Perhaps I am wrong though as newer cars do have another oxygen sensor past the cat and I'm not sure what the computer would tell the system to do if anything was different from what a factory cat might do. It should do the same thing in theory but might not last as long, which in your case seems ridiculously short already unless the first one was stolen or something. Anyhow a Magnaflow cat can be bought for less than $100 and isn't worth near as much to those who collect used ones for their precious metal contents but it will still work better than an old factory cat that's tired or had blown its innards out.
