I had the 80K miles discussion with the dealer and was basically told "you'll need a order from the Feds before we'll pay for replacement under that warranty". Not for a "cat' but emmissions related repair.

yeah at the end of the day we are still in the mercy of the dealer. I am going to go with the aftermarket and I will keep everyone posted. Hopefully the next person who has the same problem can learn from my mistakes. Thank you all and of course if there is any other info re: cats out there I should know please feel free.

One quick question to anyone that might know. I am looking at different aftermarket cats, where can I find out info on my x5's current cat (inlet size and outlet size and length) I have an 01' 4.4i where would this info be located? I tried realoem but no luck.

Try an after-market exhaust maker and see how they spec. the exhaust.
I found this link:

http://www.millteksport.com/products.cfm

It contained this info:

Your original catalytic converter will typically have 400 or 600 cells per square inch (cpsi), these original cats are restrictive in their flow, typically allowing an open area of around 55-65%.

Joe, Zulu's link is good and,
here's a look from GOOG:

http://www.google.com/search?hl=en&q...=Google+Search

I bet there are a few shops in NYC/NJ that have them to fit yours.
Like putting on aftemkt mufflers, those guys are generally pretty
good at making things "fit". $2Gs from the stlr?! I would go aftermkt.
It's a cat...
GL,mD

Thanks guys. I dont know what I would do without X5world.

Me neither!

+3 !

Quick question, I might have asked this before but I am not sure. I am buying a universal random technology cat and they have several for the x5 size wise they range from 2" inlet and 2" outlet size all the way up to 4" inlet outlet, also the length varies from 17 inches all the way to 24 inches. My question is does anyone know what size a 2001 bmw x5 4.4i take or where can I find this info? thanks again guys.

Here's a parts diagram, but it doesn't show dimensions.

I have to think that a cat mfg'er has the right size if
you offer your MY, month built, engine, etc.

And, a scooch under your car with a tape measure
should give you length at least...
GL,mD

http://www.realoem.com/bmw/showparts...90&hg=18&fg=10