Raising the rear end

I'm working on a 1968 firebird and I want to lift the rear end 1-2"
should I go with air shocks?
Or should I add a coil to the leaf spring?
I don't know about a shakle kit would it make it wiggly in the rear end?
What do you think I should use? is there a better way?

I do want to raise the front as well I have seen rubber donuts for under
the coil springs. my springs are sagging all around.
Do you think the donuts would put to much stress on the frame and lower arm?
I did use these donuts on a unibody car before and it cracked the unibody
maybe if I use a stiffer shock. :naughty:

Thank's for the help