I have these renditions of the same song that play at exactly the same tempo to the ear, but one person recorded their version at 160BPM and another at 80BPM.
 
In other words, the person who recorded their MIDI file at 160BPM was actually playing in half-time. So now the songs don't sync in Sonar because one is twice the speed of the other. The length of one file is double the size of the other.
 
Is there a way to change the version from 160 BPM to 80 bpm or vice versa without affecting the tempo? may be a CAL script.
Thanks

There is     Process> "Fit to Time"...I use it all the time with SMPTE TC.  Should be easy enough to figure what 1/2 or double the time should be. 
 
I think in the new SONAR you can grab a midi clip's end while holding down shift and you can stretch or compress.  The clip will give you a %....you want 50% or 200%

I answered this in your first thread here:
 
http://forum.cakewalk.com/FindPost/3169528