Buy a ZR2...
if you have one like the picture than its not even 4x4 so you have alot of work to do.
you CAN keep it 2wd like some of the eairlier ZR2 models came.
You should really try using the search button to find out what makes the Z so special, for example
large front sway bar
rear support bar
larger wheel bearings
single piece rear aluminum drive shaft
steering stabilizer shock
THE WHOLE FRAME IS DIFFERENT!