Wow, what a great product and solution to an expensive issue. I had a check engine code on my 2008 Toyota Sequoia 5.7L. I also had a very annoying rattling somewhere in my exhaust. I bought an inexpensive OBDII wifi reader and used my phone to read the code. I had a PO430 error meaning inefficient catalytic converter on the passenger side. Checked out the converter and it was definitely rattling particularly after it warmed up.Called several local shops and had estimates for $1500-2000 to replace the passenger side catalytic converter. I figured I would give this Walker Direct Fit Catalytic Converter a try. Bought some PB Blaster and sprayed the 3 exposed nuts on the front flange of the cat. Also sprayed both O2 sensors and the 2 bolts on the rear flange. Let it soak over night.Jacked up the Sequoia and put jackstands under the front end for safety while I worked. Took a 7/8's wrench and used it on the O2 sensors (no special O2 socket needed). The entire oem exhaust system is 10 years old but looked in reasonable conditional other than the flange bolts. I figured the O2 sensors were OK since I didn't get an O2 sensor error code and Toyota doesn't have a recommended replacement interval for the Sequoia's O2 sensors. With a very healthy pull, the 7/8s wrench loosened both O2 sensors. I was able to unscrew them by hand and just tuck them up and out of the way without even disconnecting them while I worked to removed the factory Cat.Next I took a large 1/2" ratchet with a long extension (15" plus a smaller extension). I needed a pipe to get more leverage on the ratchet and all 3 of the forward nuts on the manifold flange finally loosened. No damage and they easily unthread thanks to the PB Blaster. Unfortunately the 2 bolts on the rear flange were too far rusted. I used my sawzall and quickly cut the nuts off the bolts. Punched the bolts back through their holes and the entire oem cat was loosened and worked free. It slid right out from the rear. Once it was out of the Sequoia, I could hear the forward of the 2 cats was free and rolling around inside which was the rattling sound I heard in the cabinI needed to buy 2 exhaust gaskets from my local NAPA shop and 2 replacement bolts for the 2bolts I cut off on the rear flange. The forward manifold nuts were in good condition and I reused them. The New Walker Cat slid right into place with the new gaskets.I tightened up the 3 forward nuts. Replaced the 2 rear flange bolts and tightened them up. By Hand I threaded the O2 sensors back onto the new Cat with some anti-seize on the threads. Put the 7/8's wrench back on them and they easily tightened up.Started up the truck and crawled back under to feel with my hand if there were any exhaust leaks. No leaks. The engine was quiet again. Lowered the truck and took it for a drive. Outstanding. Lots of power was back as the old cat was definitely robbing the right bank of cylinders of power from the restriction of the loose cat.I cleared the Check Engine code with my phone and the wifi OBDII reader. I've driven several hundred miles since the cat replacement and the check engine light is gone and the power is back. The real bonus is that I was able to take my old Cat to a large recycling center in our area that buys precious metals, copper, stainless etc. Because my OEM Cat was a "honeycomb type" with 2 cats, I got $70 for each Cat for a total of $140 bucks. If it had been a "spiral type" cat I would have got $40 for each Cat or a $80 total.SUMMARY... I paid about $250 on Amazon for this direct fit replacement Cat. Plus $10 for the OBDII reader, $12 for the exhaust gaskets and a few bucks for the PB Blaster and a couple of bolts. Minus $140 for the used Cat I sold to the recycling Ctr, comes to a grand total of about $135 and a few hrs time that a shop would have charged me $1500-2000. If you have some basic tools, a few handyman skills, a jack and jackstands and some safety googles, this is actually a very satisfying job to tackle.