Definitely spike those baby's. I just spiked my SDA-1C's a couple of weeks ago (I know, it is sacralidge (spelling?)), but one of the bottom risers that were on one of my speakers was starting to fall apart, so I figured, why not try it. Nice improvement, and relatively inexpensive. It is suttle, but there is a difference in the sound! 
This month I got in a tube pre that came on spikes with metal disks to put under them if you need that.
I have a decent set up. I tried them both and cannot hear a difference. I did fire a lot of cannon in the war, so that may just be me.
I think the difference may be things like are you on carpet, glass, wood, etc.
Different things will work here and there.
I keep putting up, (many hope I will stop) often it is better if we can isolate the equipment from other things. Some claim that me dancing around will have effect on my Rega 5, not to mention taking me out of the sweet spot, but what the hell !! I play music, I drink beer and I dance on the way to the john.
Buy this, or something like this, many options are out there.
This looks high, but a sheet will do all your stuff, including those sub woofers and speakers which really can benefit from it. A little goes a long way.
