is it true that you can replace the cat on a 300zx with something called a test pipe? i did some research on them after accidentally seeing them on conceptzperformance.com. i also searched on the legalities of them but couldn't find anything. does anybody know if they are 50 states emissions legal? that would be awesome. thanks.

testpipes are basicly a replacement pipe in where your cat is located. its like a detachable straight pipe...and you do know that straight piping is illegal...because of emissions..so that means..test pipes are illegal too!!...but...they dont know that..so shhhhhh....

i knew that removing or gutting the cats would be illegal, but my concern was that it would be extremely loud. also, when you get your car smog checked, wouldn't they see it? thanks guys.

The emissions place will notice when you take it there. Only in the results though. They won't actually look under the car. It won't necessarily be louder, but it could be somewhat louder than you'd like. Silencers are sold for the exhaust system if you're concerned about excessive noise. Although they have been shown to cause some hp loss, a couple of ponies will be the price you pay for less noise.
Unless your car normally runs really clean or you live in a state that doesn't require emissions tests or tests every other year or so, you might want to look into getting high flow cats instead. Random technology makes them for the Z32. You could get the stand alone cats or with the midpipes already welded on.
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