Hey guys, 
  I am just today jumping from Producer 8.5.3 to X2,  I am doing live recordings, I have never used a loop, a synth, of any kind and don't really care to clutter up my system with stuff I won't use.  Can I install X2 Files part 1,2,3, & 4 with out the "loops and one shots" files?  Are they just loops ?   

yes..

Yes I need them all?  Or yes they are just loop patterns?   and what the heck is a one shot?

Yes, skip the loops and one-shots. A one-shot is a sound file that does not loop. You might want to do a custom install and select what you want to install from the X2 parts 1 through 4. That would allow to skip the synths in the X2 installer.

Edit...  Disregard..
 

one-shots are often (but not limited to) drum and other percussive sounds.  Like scook said, they simply don't loop.

Simply install Parts 1,2,3 & 4 and you'll have the full Sonar X2 program minus the extra loops, shots and a synth that comes with it. 

So are those for instance the sound libraries for session drummer?

No, Session Drummer and it's samples are installed with the X2 installer along with most of the the other synths. If you want to skip those samples you will need to do a custom install and skip installing the Session Drummer.

Most of the loops and one-shots download is the old Beatscape library.