Cat Interchangeability Q
#2
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There are two versions of 997 cats and neither is a plug-and-play. If memory serves, both needs some minor modifications (cutting or using longer sleeve clamps to join the cat and the muffler). Other than that, functionally they work on our 996s.
#5
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The dealer replaced the bank 2 side (internal rattle) about 2 years ago under the emission requirement. Although my diagnosis is inconclusive at this point, I think that bank 1 is gone now. So while I probably only need one, most are offered in sets and some are listed as for 997 (some say will also fit 996). Thanks again!