After living with carpet over wood floors and spikes on my speakers for many years, my wife wants to have a wood floor (maybe tile) installed in our houseThis will change the tonal balance of yr spkrs' response (usually upward). You'll get more mid-hi frequency reflections off the floor. This simply means that you probably have to change the spkr placement; you may get a more "airy", "detailed" (if slightly bass-light) sound -- and like it more.
As to the spikes you're using: you can continue using them by placing hard metal disks under the spikes (a nickel as suggested) -- but the result won't be exactly the same. Until now you've been coupling the spkrs to the floor mass... the metal disk will decouple them.
I strongly suggest you buy nothing and experiment with whatever you find at home -- or, in extremis -- just go to home depot & buy 3 vibration control puks.