Solid steel 2 shelf rack question.

I am planning for the arrival of my new Aric Audio amp and my single amp stand will be replaced with a 2 shelf unit so the Coda s5.5 amp can be on the bottom shelf and the Transcend tube amp on the top. This way I can switch between amps without lugging them in and out. Just switch cabling. Both amps will be placed on Stack Audio Auva EQ s2 footers. So the SS 3 stand is $500 and the next level up is $1800. Quite a jump! What are the differences and will it matter that much with the Auva EQ’s? any feedback would be helpful. The rack will be sitting on a concrete floor too.