Wheel spacers 1 - 1.5" questions

I have scored a set of sweet cobra wheels with F1 tires but the rear will require 1 to 1.5" of wheel spacers (have not measured, just estimating based on numbers). I will be buying friggin 3" arp studs and some-body's wheel spacers.

Do I need hub centric wheel spacers? Can the wheels just be stud centric and be right? I am running cobra rims.I plan to stack two 3/4" wheel spacers if necessary. Is my rim going to fly off in a hard corner when I downshift to 2nd and get sideways? If I ever get sideways..