I don't know the exact name of the part, I've heard it called o2 housing along with many other names, but it looks like the one in the picture of the auction listed below only I need it for a t25 turbo so it has more bolts. It's the piece in between the turbo and downpipe.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2400520856&category=6771

If anyone can help please let me know along with a price. Let me know here or at stoyboycs@yahoo.com

Thanks,
Chris

If you are using a t-25 to boost your 420a, that o2 housing will do you no good. In order to use the turbo you need to flip it over from its configuration on the 4g63. Meaning the o2 housing will be pointing UP instead of down.

yea man that o2 housing won't work for you. I know. I run a t25