just wondering if you could put the zr2 highrider suspension on a 2002 sonoma crewcab.  

I don't know much about Sonoma's but I doubt it.

Is your's coil or torsion bar? What is the highrider? if they are the same in that regard then it may be possible.  

THE ZR2 HIGHRIDER SUSP. IS ON THE REG. CAB AND EXT CAB P-UPS. TO ME, YOUR CREW CAB LOOKS TO BE SITTING ON THE EXT CAB FRAME, JUST A NORMAL 4X4. SO THE SUSP. SHOULD FIT UP FRT. OUT BACK YOU MAY HAVE TO MODIFY THE SHACKLES AND HANGERS TO ACCOMODATE THE LONGER LEAFS FOR THE REAR. BUT IT SHOULD WORK OUT FOR YA.
GMC MADE THE CREW IN THOSE YEARS THAT HAVE THE RARE ZR5 OPTION THAT WAS A LITTLE TALLER MAYBE 2" FOR A LITTLE BETTER OFF ROADING.
HOPE THAT HELPS OUT ANY