rubber feet for B&W DM305 speakers?

I heard that adding rubber feet (from Home Depot) to these speakers will make them sound better. Any thoughts on this? What size feet? Also, how do think Polk RT15i speakers would work for rears with the DM305s and CC3 center?
No rubber feet, you want to ground them to the floor with wide heavey bases bolted to the bottom of the speakers with some weight on top of your speaker to push them down to the floor.
this is a disclaimer since i sell them on audiogon. if you would like to try rubber feet try sorbothane round isolation pads. they are an inexpensive way toisolate and dampen vibration. they would work well in all the applications you describe. again i am a dealer. check my ad.

NO. Use spikes.
I agree with Timo. SPIKE IT! John
Shame on us all for pushing our individual preferences without seeking complete information.

Nobody asked Mr. Fishcall what kind of floor he has, which makes all the difference. Coupling speakers to a highly resonant suspended wood floor might cause far more problems than it solves, like boomy bass and transmitting tons of vibrational scum into his component rack. OTOH, de-coupling from a solid concrete floor might soften bass response and transients with little benefit.

We need more information before we can offer a properly useful answer.