Does anyone have their Sub on an Auralex GRAMMA? If so is there any noticeable improvement?

I currently have my X-12 on carpet over concrete and with the spikes there is only about 1/2" clearance from the bottom of the sub to the carpet. (Can't slide my hand under it)

I'm concerned about bottoming out if I crank the sub. Does anyone know what the throw of the X-12 is? All the manual says is "long".