Leaning?? You mean like this guy?

... oh, and dude, Kim Jong Il for an avatar; really?
http://lmgtfy.com/?q=kim+jong+il

But in answer to your question I believe we've got 2 1/4" exhaust, might be 2 1/2" though. I know a sure fire way to find out for sure though. Or, the search on this site actually doesn't work too bad; try the term "exhaust size". It looks like there are several pages within the results which will be helpful in your research.

 

X2 I believe it's like 2.25 at the Y-pipe then 2.5 at the muffler and back.

 

You should go to a custom muffler shop.Definitely replace the stock Y pipe and the muffler.Here`s what my Flowmaster 40 sounds like with the rest of my mods.See my signature.

 

so shadow, you got the 40 series, full system or muffler? and what tips did you add.
funny, almost every xterra guy i know, kn ow you lol.
and did you paint our front peice black gloss? or..
thanks

 

It`s a full system with the back 2 cats cut off.Click my Cardomain link to see the custom Y pipe.The pipes are 2 1/2" in and 2 2" out.I got the tips on ebay a couple of years ago.Thet`re SS and each 1 is 3".I pulled the front panels off to paint the billet grill black and thought while I had it off I might as well do the rest.I had a shop paint the plastic pieces gloss black and clear coated.

 

I went with a Flowmaster super 40 with 3" piping from cat to back. Had the shop build a new Y-pipe with the same piping diameter.

http://www.youtube.com/watch?v=duMVPPf2gjA

 

Nice.Like to hear it revving up and maybe take off like mine.I took my video before the Superchips tuner install.Much quicker now.

 

nice looks awsome. if ur wondering, i cheaped out on the full system till i get enough money, and went with the flowmaster super 44 off road series muffler, and soon tips. Iv seen people do just the muffler, and it still sounds great. im gonna go with ebay tips, anybody know what size tip the x2 takes normally?
ill post a vid when they're on.