once and for all

I have been reading all the threads (thank you to everyone for all the wonderful advice!) My question has been asked before, but i am still unsure. I have hair just below my shoulders. It is naturally curly (been fighting THAT my WHOLE life) and has a tendency to frizz if not dried properly. I am dying to get the CHI Transformation System, because i would love straight, sleek hair. My stylist tells me my hair is in great condition. Instead of blow-drying, i usually put in a leave-in conditioner and put it up to air dry. Here's my problem (finally), i have had to color treat my hair since my early 20's because most of the roots grow in gray(hereditary). For the past couple of years i have used Clairol Color Charm which says that it deposits and doesn't strip hair. My hair is a very dark brown, so all i need is to cover the gray roots. Can i use the CHI TR System, and still use this haircolor? Not coloring is not an option. I have colored after having a straightener called Straight Talk put on my hair (many years ago), and didn't have problems with it then. Please help! I appreciate any advice..thanks!