It doesn't what set-up or brand you use or who you buy from. But if you go over about 10% overdrive you'll need injectors.
You basically have two choices. Metco/Innovators West or ATI. Different vendors sell one or the other. Both do the same job.
http://www.metcomotorsports.com/prod...CP-LSA&cat=118
http://www.atiracing.com/products/da...serp.htm#Zbody
Here you see all the pulley sizes(CTS-V is the same as your ZL1)
http://www.atiracing.com/products/da...mserp.htm#CTSV
Check the classsified section over at the CTS-V forums.