20s for the Demon - how low can I go? (big wheel haters don't look)

That looks good, I have the same wheels on my 96 Ram haha. See if you will have enough ground clearance in the front if it was 5 1/2 to 6 1/2 inches from the ground. That would be a sick ride, I like re-using factory stuff so I hope it all works for you!