What's wrong with my catalytic converter and what brand should i replace it with?

I have a 98 Honda Odyssey. My brother pulled off the cat cause something was rattling when i hit the gas and dumped pieces out of it. I want to order another but for now he just put the old one back on after removing the pieces. At Honda it's 900$ I have read that If i use a non oem part the code may not go away because the computer on the van won't recognise that the problem is fixed. I've also read you can clean them but after pieces break out? What causes the pieces to break off inside? There's a website called partgeeks that says they have the right one for 170ish. What should i do? I love this van i don't want to cause further damage but i can't afford 900$. Thank you also does anyone else with this car have a jolt when taking off from slowed down speeds? Transmission has been rebuilt and checked again twice.

When an online site says they "have the right one" it doesn't mean it is OEM. But phone and ask. Try to find an online OEM Toyota parts reseller. Assumes you can install yourself. You are on the right track wanting to use the OE factory part. Assuming that is your problem the electronics, the O2 sensor etc will recognize the part not to mention if your state has a smog cert program it should/will pass. The OE part will be more expensive than aftermarket but high likelihood it will work correctly.

Use an aftermarket part. It will do the same job the only difference is it may not last as long.

Go to rockauto.com.

Buy a Walker or Eastern Catalytic. Those are very good aftermarket brands.

First, fix the engine misfiring problem that damaged the Honda converter.

Read these two posts to find out why converters fail and how to break in a new one.

http://ricksfreeautorepairadvice.com/catalytic-converter-problems/

http://ricksfreeautorepairadvice.com/catalytic-converter-break-in/

Direct fit Walker Catalytic Converters can't be beat! Price them @ autopartswarehouse.com, partstrain.com or rockauto.com

Before you get a new CONVERTER< there are things you need to know about all this mess! You need to eliminate the CAUSE of the problem! YOUR CONVERTER over heated due to a BAD AIR/FUEL MIXTURE! Excessive GASOLINE caused this problem for you! When a converter OVERHEATS< the inside GLOW and the matrix breaks down! The REAL issue is a dirty IDLE AIR CONTROL VALVE and THROTTLE BODY and YOUR oil choices! BAD OIL sticks the IAC and it stops working in stop and go conditions! If you ONLY drove on the highway, you may not have issues! IN the CITY driving mode, the IAC is called upon to add EXTRA AIR as required to keep the CONVERTER temperature LOW and the CARBON output even lower! <<<<UNTIL YOU CORRECT the cause, you will burn out NEW converter as well! <<TAKE $20-40 to ANY oil change place and have the THROTTLE BODY and the AIR CONTROL VALVE cleaned up to SHOWROOM clean! You may be able to keep the BAD converter longer by doing so! Even with pieces missing, IT WILL STILL GET THE JOB DONE! Until the IAC and T body are SHOWROOM CLEAN again, the AIR FUEL mixture will be OFF center and it will OVERHEAT as well! BTW< you do NOT have a "GAS" pedal at all on modern cars! It is ONLY an "AIR PEDAL" YOu add AIR to the injected fuel and the IAC adds MORE air as required to keep the CONVERTER running COOLEST and in that proper temp range! If you GET THIS< you are smarter than 90% of other people, even mechanics! DO NOT REPLACE converter til you solve the AIR fuel mixture issue! Was your CEL light on a while! BAD OIL also causes this over time, too! The use of WAX BASED oil makes tar that BAKES into engine parts and even into converters! MOBIL ONE 0W-30 will SAVE YOU in costs over time!