Floor spikes again...

The floorstanding T-M-M speakers I'm building are 8-1/2" wide by 10-3/4" deep by 44" high, and sit on a carpeted concrete floor in the lower level of our home. I was planning to add four spikes to the bottom of each somewhat top-heavy speaker to penetrate the carpet and increase its stability.
I see that many people place little metal cups under speaker spikes, presumably to protect the floor. Wouldn't these just eliminate the value of the spikes?
Also, I've read that using spikes increases speaker cabinet vibration. I'd assume this is a bad thing in most circumstances, but does it all come down to the room and personal taste?
 
I view speaker spikes as snake oil. I haven’t seen any measurements that show they do anything. Mesurements and studies may exist but I haven’t seen any. I recommend you stop chasing shadows and instead build a solid base for your speakers. I can hear a difference in sound from my speakers by turning my head or slouching in my seat. I doubt spikes could make that much difference. Last, if your speaker boxes are transferring energy to the floor you simply need to build a better box.