Hey, I just became the proud owner of a 1995 pathfinder XE. It has a 3.0 v-6,auto, and a limited slip. It has 245/70 duelers and and mag wheels. It has a drop in K&N air filter , a glasspack muffler and new plugs. It runs great but doesnt build any power down low. Does any buddy make a cam for it.Is there a header out there that just bolts in and doesnt need the oil filter moved out of the way. Any help would be gladly accepted.Thanks.  

Check out www.4x4parts.com they have lots of performance parts that are specific to Nissan.  Like these headers:
https://www.4x4parts.com/catalog/index.php?cPath=367_266_350

Also, I have heard from a number other with that engine that if your exhaust is too wide open you are going to lose the low end (which is typical in most cases).  You might even try to go with a performance muffler that still has some restriction but less than the OEM system.