The best sealing option for your VR30DDTT upper cats to lower cats or lower down pipes is here. The CZP XT or eXtra Thick gaskets are custom 1/8 inch thick high temperature graphite gaskets with a stainless steel mesh core precision cut to the exact OEM gasket dimensions, sure to be the last gaskets you need. These gaskets have no issues sealing with slightly warped or "problem" flanges and give you the peace of mind that you wont have any pesky exhaust leaks anytime soon. Just make sure each flange is clean and clear of debris, install your hardware and make sure the gasket is slightly crushed and you should be back on the track in no time.