I have the Monroe strut mounts from rock auto, about to put them in along with the Bilstein 5100's as well.
I'd say ya get what ya pay for, but they may be made in the exact same factory and put in a different box.
I am leaving my strut spacer in and setting the Bilstein second from the top as I have the Z71 springs in the rear, with an extended length Bilstein. I'd rather have the suspension travel than the added preload in the front. Mine will have a softer ride vs someone that sets the Bilstein strut at the lowest/lower ring setting, while having the same height but without a harsh ride..
Just something to think about. Spacer isn't that ******* anything. And it may extend the life of the strut since it will have less preload and more downward travel.