I was skeptical going aftermarket, because the stock car had 200k on it but for $500 for only one cat through the dealer I couldn’t justify paying that...I only need the bank 2 cat but replaced them all due to mileage along with new gm o2 sensors. The studs in this kit are exact thread pitch as stock (they do not provide the nuts however) so reuse your originals. I was not a fan of the provided studs so I heated and removed my originals and installed in these new cats.If replacing the most rear cat that connects to the flex pipe this kit does include four bolts and nuts/washers for that (they are different pitch than the originals) but work just fine for installation as the stock flex pipe used knurled studs that typically break upon removal, so having hardware in this kit is a plus.Gaskets are also provided.....save yourself hundreds and buy these along with Walker 50484 and your on the road for less then ONE converter at the dealerMy skeptical reasons were justified on install but we shall see the truth in how long they last.....