Does anyone have detailed instructions on how to install a header on an xB? I lost mine...thnaks

you can figure it out, whatever you take off you put back on.

5 nuts/bolts on headers holding it to head, use an offset wrench for these and it'll make it a whole lot easier. 2 spring bolts connecting downpipe to headers. 1 bolt on bracket of headers (i believe, been a while) near bottom of headers, you'll see it when you're under. After you get all those off the headers come off. You'll need a new gasket (don't reuse old). Toyota sells them for 28 bucks I believe, it's a crush gasket so you definately don't wanna use the old. Put the gasket on bolts on the head, put your new headers in place, reattach loosely just to hold them up. Connect your downpipe to your new headers (easier when it's loosed so it's got some play in it (the spring bolts people have a hard time with, i used an airgun so it went quick). The one bracket bolt you removed from the old headers you don't need anymore, you can just screw it back in or do whatever with it. Connect the headers back up and you're good to go.

If you have anti-seize you should use it on the header bolts to keep them from locking up, just in case you need to get them off later.