Remember, that in California, almost any exhaust work is going to cause you to fail. You can do axelback exhaust and be good, but according to the vehicle code book, if you move, alter, change, remove, etc your catalic converter you wil fail. Also note that there are several parts to the test...the measuring of HCs and COs from the exhaust, the "sniffer" test, and the visual test. Whenever you get a part that says "not legal for sale on pllution controleld vehicles" usually means that item causes your engine to emit more HCs and COs than allowed.
You alternatives are 1) to keep your orginal parts, 2) seek a non-reputable shop to "fake" a passing test (not a good way to go for not legal and will get caught sooner or later), or 3) register your car in a part of California that smog is not required (again, not totally legal).