I did a couple serches but couldn't find anythign close to this.
Has anyone tried to bore the V6 in the X? Last Jeep i had i took to 60 over and replaced the pistons as well as some other engine components. Not sure if its the age of the I6 or the popularity of Jeeps but it does not seem like there are to many spare performance engine parts to be had for Xterras.

If anyone knows a good wherehouse or shop that may have reliable engine pieces please let me know. I have a machine shop to work in but im not about to start fabricating heads and pistons.